Paper For Sighting In

Perhaps you've had trouble sighting in.  Your first shots aren't on the target, and there's so many holes in the backer, that you just don't know where your shots landed.  You have someone spot for you, but they only see dust kick up from somewhere behind your target.

You need to cover that backer with something, right?  But what?

As it turns out, there is an inexpensive solution readily available.  I found tissue paper at the Rite Aid next to the wrapping paper and gift bags.  For about $3, I got 24 sheets about 2 feet square, which is enough for me to sight in probably 8 times, using several sheets at once to cover the backer.  .22 caliber bullet holes with the soot rings aren't too hard to spot through a spotting scope at 100 yards on the white tissue paper.

If it rains, then you're on your own. =D

Cabela's/Berry's Tumber Review

For a little while, very little while, I cleaned brass with soap and water, dryed in the oven, and polished by hand with steel wool.  That got old really quick, and I ended up with a few splinters of brass or steel wool in my fingers.

Of the tumblers that were getting good reviews, the Cabela's model and the Berry's were two of the cheapest.  With the exception of external appearances, the two are really the same.  Berry's makes the tumbler for Cabela's.


I believe that the instructions that came with the Cabela's tumbler said to fill it 2/3 with media, and then load in the cases.  The cases seem to come out cleanest and nicely polished when the tumbler is completely filled, and the motor doesn't seem to mind the full load.  You don't have to fill it, obviously, but that's how I get the best results.

I run the tumbler 3 hours with a timer.  Once-fired brass, if not too badly tarnished, comes out nice and clean.  I probably don't need to tumble the once-fired brass from the indoor range the full three hours, and should probably cut that back in the future.  The cases I reload with TiteGroup powder sometimes get scorched, and the tumbler doesn't remove that burn mark.  I don't think that much of anything would remove the burn marks.

I store my cases in 1 Gallon Zip-Loc type bags, and the tumbler will hold about a half gallon worth of brass when filled 2/3 with tumbling media. 

Although I'm not sure when I received it, I ordered it on 2/5/2007, and it's still going, knock on wood.  When I first got it, I didn't have a whole lot of brass, and I was doing a lot of small batches, so I've got a good number of hours on the unit.

Capacity (approximate):

900 9mm casings
550 .45ACP
500 .38SPL
450 .223REM or .357Magnum

Tumbling Tips

You can get big bags of KayTee brand crushed walnut shell at some PetSmart stores sold as bird litter.  It is much cheaper than the stuff sold by reloading suppliers.  I add in some paste brass polish that I picked up from the dollar store, but I hear that NuFinish car polish works well also.

When/if you add liquid or paste polish to your tumbling media, run the tumbler for about 30 minutes without any brass.  If you put in the polish and the brass at the same time, all the polish will end up caked into a few pieces of brass.  It's not good, trust me on this.  If you were tumbling bottlenecked rifle cases, you might have to throw out the pieces with polish and tumbling media stuck in them.

Get yourself a dust mask.  The tumbling media will pick up lead from the primers in the cases, and you don't want to breathe that in.  Besides the lead, dumping the media into a sifter will generate a lot of dust that you'll choke on anyway.

Run your tumbler outside or in your garage where any lead that might get out of it won't contaminate your living space.  The motor in the tumbler can get hot, so don't put it on anything that might melt or ignite, like nylon carpeting or newspaper.

Cabela's Website - It's the model 400 tumbler.  Check RetailMeNot for coupons.
Berry's Mfg. Website - Model 400 tumbler.

WARNING: Vibratory tumblers have been known to attract graboids.  Use at your own risk.

Midway Coupon Code, Expires 10/21/10

From GlockTalk:

Place $50 or more of in-stock products in your shopping cart. Enter Promotion Code 105028104 in the box entitled 'Promotion Code' on the Shopping Cart page.
You will see the discount on the Confirmation page before placing your order.
Remember, this promotion code is valid for orders placed on MidwayUSA.com.
Limited to one per Customer and one promotion code per retail order.
Offer cannot be combined with Birthday or Special Pricing.
Offer not valid on MidwayUSA Gift Certificates and Nightforce products.
Hurry, offer ends at 11:59 PM CT February 21, 2010.

Zel Custom Tactilite T1 .50 BMG Upper Recall

 

From Zel Custom Website:

Recall Notice - Potential for Very Serious Injury. If you have a Tactilite T1 .50 BMG with a bell-shaped handle with 3/16" threading and a roller, there is the potential for out of battery detonation.  If you have a unit that fits this description, regardless of whether you have fired it safely in the past, we ask that you contact us immediately to arrange for replacement components.  We are not aware of any incident of an out of battery detonation or any injury. However, we have been able to make this happen in our shop and out of caution we ask that customers contact us immediately to arrange for free replacement components.

Armalite AR-10 Mag Sale

The Official Armalite Website
Direct Link To Magazine Sale Prices

5 pack of 20-round AR-10 mags - $150
10 pack of 20-round AR-10 mags - $275
I've never seen Armalite AR-10 mags for less than $45!  They have other magazine capacities available on sale too.

New GSG-5 Rimfires

You may have heard that American Tactical Imports was given a cease and desist notice by Heckler & Koch, because their GSG-5 line looked too much like their MP-5s.  To get around this, ATI has changed up the GSG-5 guns a little bit.  The new guns, a whole range of pistols and carbines, will be called GSG-522.

The ring around the front sight is replaced with vertical "ears," the rear sight has open slots instead of apertures, the magazine release was made wider, a Picatinny rail was added to the top of the receiver, the pistol grip was given a stippled texture like a Glock RTF frame, and a sling attachment loop was added to the front of the trigger guard.  Appearance-wise, the "cocking tube," charging handle, and selector switch have changed.

Christopher at ATI says that parts from the original GSG-5 will be available to those who want more of an MP-5 clone, but that the manufacturers, distributors, and dealers can't sell them that way.

Also new is a 110 round drum magazine!

You can read a little more about the new GSG guns, and see all the pictures, in this AR-15.com Forum thread.

40 Reasons For Gun Control

I'm pretty sure that I've read it before, but here it is.

40 Reasons For Gun Control, from The Kentuky Coalition to Carry Concealed.

I'll add it to the Links page in a minute.

More Guns, Less Crime In Wash. D.C., 2009

Besides the panic buying after the election in November '09, residents of Washington D.C. were going to gun shops for the first time, after the Supreme Court's ruling in D.C. vs Heller, that the disctrict could not reject all requests for handgun permits, and require that all other firearms be unloaded, locked up, and disassembled, so that they would be useless if needed for self defense.

(Supreme Court Ruling in PDF Format)

Washington's crime rate had risen in 2007, while crime rates fell in most cities across the country.  The Washington Post reports that, "The District is on track to have fewer killings than in any year since 1964."  The ban that was repealed after the Supreme Court decision, went into effect in 1976, by the way.  The Post credits faster reporting of crime via cell phones, better police relations in the community, and higher homicide closure rates for the decrease of crime in the city and surrounding areas, but I find it dubious at best that this turn around all happened between 2007 and 2009.

The gun ban lobby once again predicted bloody battles in the streets, but the police in the nation's capital report a 23% drop in homicides in 2009.  As the Supreme Court case was being heard, D.C. mayor Adrian Fenty had said, "Whatever right the Second Amendment guarantees, it does not require the district to stand by while its citizens die."  Shorty after the Supreme Court ruling, Mayor Fenty said, for the record, “I’m disappointed in the Court’s ruling and believe introducing more handguns into the District will mean more handgun violence.”


Second Amendment supporters knew better, though.  It's not hard to find similar cases where crime fell as gun control laws were lifted.

(this post was inspired by the "Gun News Ticker" in the January 2010 edition of The Gottleib-Tartaro Report, a 2nd Amendment Foundation publication)

Bushmaster Dropped a Bomb at SHOT Show!

Bushmaster has released the ACR rifles for sale.  Don't get too excited yet, though.  There's a catch.

Link to The Firearms Blog  Bushmaster ACR post.

Link to official Bushmaster site, ACR Launch page.

The basic model has a single top rail, and a fixed stock (yes, confirmed, fixed non-folding stock).  Retail price, $2,685.

The "Enhanced" model has a 3-rail handguard (in addition to the "monolithic" top rail), and the collapsable folding stock.  Retail price, $3,061!!!

Crap, dude!?!  What happened to $1,500!?!  I had expected that they'd sell for about that price for the first few months, but I expected the dealers and distributors would reap most of the profit, by marking up over the retail price.  I don't know how much room there's gonna be to mark up the price.

Bushmaster is pretty well known for poorly assembled rifles (check this out).  For those prices, these damn things had better be perfect.

Barrels are 1:9" twist, which limits you to bullets that weigh 69 grains or less (depending on the precision of the rifling twist to spec).  Not a good idea.  Many serious shooters prefer 1:7" twist for shooting 77 grain bullets including the U.S. Mk262 load.

EDIT: 1:7" twist barrels will be available.  It is unknown, at least to me at this point, whether it will be an extra cost upgrade, a no-extra-cost option, or a separate accessory barrel.  (Thanks for the reminder, Drew)


Barrels are hammer-forged with an "innovative coating," FWIW.  Not chrome lined.

Disappointing to say the least!

The Robinson Armament XCR is looking a lot better.  I've seen them at gun shows for about half the price of the basic model ACR, with most of the same features.  The FN SCAR is also quite expensive, but now available in black, by the way. (NOTE: SCAR article in the new issue of Guns Magazine, and may be available online already)

I'm thinking I'll upgrade a couple of my AR-15 uppers, and wait this one out.


Also from The Firearm Blog, Colt is releasing a civilian version of the Sub Compact Weapon (SCW), an AR-15 based, folding-stock rifle.  Full details unknown at this time.

Endine AR-Restor Carbine Hydraulic Buffer

Packaging, left.  Hydraulic buffer, center.  Standard carbine buffer on right.

With the buffer installed with a 9mm upper, the rifle had a weird double recoil impulse.  It was sort of a ka-chunk effect.  Since it didn’t have any noticeable effect on performance, I went back to using the RRA 9mm buffer.

Shooting .223Rem ammo, I didn’t really notice the double recoil, but it still didn’t seem to have any noticeable effect on recoil control.  My 16” LMT M4 upper ran okay with it installed, but the 10.5” LMT upper was hanging up.  The 10.5” upper only ran well with a carbine buffer; I had the same problems with the “H buffer” though.

The 10.5” upper was run on full-auto.  Again, I still didn’t see any really noticeable increase in control.  Rate of fire didn’t seem to be slowed down much, although I didn’t try to measure it.

None of the uppers I tried with the Endine buffer would consistently lock open after the last round.  I tried the buffer in another lower, and got the same results.

My suggestion would be to skip the Endine buffer, and run the heaviest mechanical buffer that will still allow your rifle to function properly.  You can just about buy a carbine buffer, an "H buffer," an "H2 buffer," and a 3-pack of buffer springs for the price of the Endine buffer.

The 10.5” upper showed an obvious preference for the standard carbine buffer.  My 16” LMT upper will run on the carbine buffer, but seems to run a little better with the “H buffer.”  Some rifles will run with the “H2 buffer,” but I personally haven’t come across one yet.  When running a 9mm, you should run one of the 9mm buffers, but an H2, or H3 buffer might work.

Just as an FYI, buffers are marked in the center.  Standard carbine buffers will have no markings.  Heavy buffers will be marked with an "H," "H1" (same as the "H", but markings vary by manufacturer), "H2," or "H3."  The "H3" buffer I ordered for an AR-10.  I don't think my 9mm buffer is marked, but it's black instead of the usual yellow zinc color.

M&P 9 Pro Is Back From S&W

Aha!!  My M&P will now eject brass without pissing me off!  Similar to my 1911, except for the vigor of the throw, the brass is going out at around 4 to 5 o'clock, rather than 5 to 7 o'clock like it was doing before.

A note that followed the pistol home read:

REPAIRED: BARREL MODIFICATION

REPAIRED: REPLACE EXTRACTOR

REPAIRED: INSPECTED/TESTED & PASSED

I'm not sure what they did with the barrel.  It looks the same to me, with no obvious signs of modification.

I did have one rather odd malfunction while testing it after I got it back.  I pulled, and pulled, and pulled on the trigger, and it didn't fire.  The striker wasn't cocked?  I went to rack the slide and it was sticky, but with a sharp tug I got the round out of the chamber.  I loaded the round back into the mag, and continued shooting until the pistol was empty.  I didn't think to look at the round that it hung up on.  Hopefully there was just a burr on the brass casing that was holding the slide out of battery, keeping it from firing.  I dunno.  If it happens again, I'll note it.

Reading through the Pistol-Training.com blog's M&P torture test posts, it looks like Todd had a similar problem, with the trigger not resetting.  Weird.

I plan on taking a couple carbines out next time I go shooting, so it may be almost a month before I get to shoot the M&P again.  I have an LMT upper that didn't pass with a headspace GO gage, but seems to work with a carbine buffer, if not the "H" buffer.  The tech guy at LMT said the headspace is supposed to be tight, although it seems strange that it wouldn't pass with the GO gage.  I dunno, I'll have to see if it breaks in a bit or just functions anyway.

2010 Glock Annual Magazine Is Out

Time for the Glock Annual Magazine.

GlockTalk Glock Annual Magazine thread.

Team Glock Glock Annual Magazine Request Page.

New Year's Resolutions

Put pictures in more of the posts. (I'm getting better!)
Set-up some kind of light box so that my photos look better.
Post more reviews this year. (Tapco G2 trigger, Green Eyes and Black Rifles book, fiction books, more optics)
Cover things I learn as I get more into loading rifle ammo.
Keep the Articles and Reviews pages updated. (I'm a little behind)
Post links to manufacturer's websites, and other relevant links.

John Farnham on "Convenient Fantasy"

You're probably not as safe as you think you are.

I've been reading through John Farnham's Quips from the Defense Training website.  The following is from his quip entitled, "Convenient Fantasy."

When you are not continually equipped and prepared for an instant, precise, and lethal counterattack, any "safety" you're imagining is a convenient fantasy. Like cheap insurance, it all works just fine- until you have a claim! Enjoy it while you can.

I suggest that you read the quip.  It will only take you 40 seconds or so.



Oh, and Merry Christmas!

TangoDown Stubby QD Vertical Foregrip

 

TDI/CAA K-Grip and TangoDown Shorty Grip

The TangoDown Shorty VFG is interesting in that it’s not round, or symmetrical.  Some thought was put into making it ergonomic.  The length of the grip is just long enough to get my whole hand around, but it’s not really designed for you to put your thumb around the back of the grip.  The stubby grips are really for people who put their weak-hand thumb pointing forward on the weak-hand side of the carbine.

Bottom View Of Grip Showing Teardrop Shape

Weak-Hand Thumb Forward VFG Grip

The o-ring-sealed compartment in the grip is just large enough to hold 2 CR123 lithium batteries, while still being sealed watertight by the o-ring.

The quick-detach mechanism is made by American Defense Manufacturing.  To remove the grip, you push in the release button and flip the lever out ninety degrees.  You can then pivot the grip off the rail without sliding it off the end of the rail.

I think the QD lever is worth the small increase in price over the standard TangoDown VFGs.  I can remove the grip to get the carbine into a rifle case, if necessary, or just to shed weight.  I can also swap it over to other firearms quickly, without tools or removing rail covers.  It’s also compatible with a wider variety of non-spec rails than the standard VFGs.

I like the QD lever of the Larue products a little better than the ADM lever, but the ADM lever is quicker and easier to adjust.  The Larue locking mechanism is more positive.  It’s possible to only partially press the button of the ADM lever, which won’t allow you to move the lever.  However, adjusting the Larue lever required a wrench and some trial-and-error.  The ADM is quick and easy to adjust by turning the screwhead opposite the lever.  The ADM clamping system is less likely to mar your rails than the steel tab of the Larue locking lever that actually holds the mount or VFG to the rail.  The big tab on the bottom of the steel Larue lever bears directly on the rail.

Larue QD Lever Mechanism Compared To ADM QD

ADM QD Clamp Adjustment Screw

Standard Larue Locking Lever, Showing Adjustment Mechanism

I’m not going to get into testing durability.  TangoDown grips have been around for a while, and have taken some serious abuse by military and civilian users.

Midwest Industries T12 Handguard

Before - Pretty Basic M4, Aimpoint is a very new addition

After, along with some other upgrades

Instruction Sheet

Midwest Industries (MI) is now making one-piece float tubes, in addition to their two-piece, no-gunsmithing, float tubes.  The one-piece tubes use an aluminum barrel nut rather than the steel G.I.-type barrel nut, which saves some weight.  The handguard itself requires less material than a two-piece float tube, saving a little more weight.  The one-piece tubes are also cheaper than the two-piece tubes, at about $155 vs.$228 for the 12" versions.

I was afraid that if I bought one of those $300+ handguards then I’d be afraid to really use it.  That, and I’m too cheap to drop that kind of cash, when I can get almost the same thing for about half the price.  I went with the rifle-length handguard on a 16” barrel because the rail I had bolted to the bottom of the plastic M4 handguard was proving to be too short.  I was pleasantly surprised with the MI Low-Profile rear sight, so I gave MI a shot with the railed float tube.

I’m liking the rifle-length handguard on the carbine upper.  I think I have more muzzle control with the vertical grip mounted farther out from the receiver (like Kyle Lamb says).  The extra length gives more freedom in bracing the rifle against hard cover without the barrel touching anything.  It gives a longer sight radius too, obviously.  It was worth the extra 2 and half ounces (15.4oz., rather than 12.9oz.), over the 10” handguard, I think.  Weight of the 12” Daniel Defense Lite tube (currently $332 at Bravo Company), by the way, is listed at 14oz.  The 12” Lightweight YHM tube (currently $139.95 at Bravo Company) weighs 14.75oz.  Price of the MI T12 at Bravo Company is currently $155, to give you a little bit of a comparison.

The handguard comes with the required Allen wrench for installation, a small vial of threadlocker, and a decent instruction sheet.  It doesn’t come with a spanner wrench for the locknut.  I might have bought a spanner wrench, but there wasn’t any available when I bought the handguard, so I just put the blade of a screwdriver in the slot of the locknut and tapped it with a hammer.  With the help of the threadlocker, the locknut is holding tight, and somewhat to my surprise, the screwdriver didn’t leave a mark on the ring.

Installation on an already assembled upper will require removing any muzzle device present, the gas tube, the front sight tower or gasblock, and finally the delta ring assembly or barrel nut.

Tools required:
1/16” pin punch for the gas tube roll pin
3/32” pin punch for the front sight tower pins (if present)
Hammer – claw hammer at minimum, those front sight tower pins can be tough to start moving
Grease – for removing and reinstalling front sight tower or gas block, and rust preventive on the barrel and steel parts covered by the tube
Degreaser – for cleaning MI barrel nut, lock nut, and anti-rotation screw before applying threadlocker
½” wrench, or large crescent wrench for muzzle device (if present)
Some sort of barrel nut wrench (should be under $25)
Vise
Upper receiver block (Model 1 Sales action block is about $35)
Torque wrench for reassembly (31 foot-pounds minimum, up to 80 foot-pounds is desirable to break-in the threads of the barrel nut, per the TM)
MI lock nut spanner, or hammer and flat blade screwdriver

I removed the sling swivel from the front sight tower, and shaved it into a low-profile gas block which required more tools – drill and 1/8” drill bit, Dremel rotary tool, cut-off wheel, stone grinding bit, files, and black BBQ spray paint.  I don't trust the set-screw type gas blocks, and didn’t want to spend $50+ for a clamp-on gas block.

Don’t forget to order another crush washer for the muzzle device if you want/need to use one.  They aren’t reusable (yeah, I tried; not enough friction to hold the flash hider on).  I think the peel washers are reusable, but I don’t like them, so I’m really not sure.

Anti-Rotation Pin Screws Into The Tube, Locking It In Place In Relation To The Barrel Nut

The handguard has an anti-rotation screw, very similar to the ones used with YHM tubes, except that it has a socket head rather than a slotted head.  The barrel nut also is very similar to the YHM nut.

The only issue that I’ve had with fitting things to the handguard was with the Vltor Scout Light mount.  The scout mount fit, but the rails on the handguard seem to be oversized, and the mount would not clamp the flashlight solidly in place without a little shim that I cut from a soda can.  The scout mount worked fine on the rail of a flattop upper, so it’s not the Vltor mount that’s the problem.

The Yankee Hill front sight, MI sling mount, Larue QD scope mount, and Tangodown Quick-Detach Vertical Foregrip all fit fine.

The only real complaint I have about the MI handguard, is the finish.  MI advertises that all their stuff is hard anodized, but I’m finding that it scratches really easily.  I was finding scratches before I even really used the rifle.  Not a big deal, but it might be if you really want a pretty “safe queen.”  The matte black coating on the Larue Beverage Entry Tool has held up to opening many “adult beverages,” so if you want a tube with a tough finish, you might want to give a Larue tube a try.

Non-spec rails aside, the handguard is okay.  It works with many accessories, but not all of them.  My newer YHM Lightweight hanguard seems to be made to the proper spec, and has worked with everything I've tried on it so far.

EDIT, 6/30/2010: It seems that MI customer service is pretty aweful.  Check MarylandShooter's site for more details.

EDIT, 9/28/2010:  When I went to check the locking ring on the handguard with the YHM spanner wrench, the nut was pretty loose.  It might have been okay, but the wrench does seem to allow more torque on the nut.

Yankee Hill QDS Folding Front Sight

Why the M4-type ears, instead of the HK-type wings that wrap around the front sight? The same reason Chuck Taylor warned about the rings around HK front sights, and why Noveske was psyched when Troy released their M4-type front sight. The front sight is not necessarily centered in the ring, or semicircular wings, and in a snap-shot scenario, you might try to center the ring or wings in the rear sight, rather than the front sight itself. This would result in a bullet going somewhere you hadn’t intended.

When I first started fiddling with the sight, I was a little concerned. The button was stiff, and the sight was harder to deploy than I would have liked. After playing with the switch-sightblade (yeah, I know, sorry) for a little while, it loosened up, and it’s now quite acceptable.

You push the button on the side, it flips up, and locks in place. I'm a little afraid that a hard knock might do some damage, since it locks when unfolded, even though it doesn't need to lock since it's spring loaded. Maybe I'll take it apart and fix it so that it doesn't lock open someday.

I unscrewed the A2 front sight that came with the sight, and installed the Trijicon front sight with tritium insert that I had in the standard A-frame front sight base (that I hacked off). I got the carbine sighted in pretty quickly. The front sight isn’t hanging far above the wings, and I didn’t have to make any significant adjustments to the rear sight.

The sight comes with the required Allen wrench for mounting the sight, and it clamped onto my Midwest Industries handguard with no issues.

Although I would prefer a sight that doesn't lock when deployed, it does lock when folded, which I did want, and I wasn't thrilled with the wings or locking designs of many of the competing flip-up front sights. I took a bit of a gamble on the Yankee Hill sight, and it paid off. Next time I need a clamp-on front sight, I think I’ll be buying another one of these.

Midway Coupon Codes for December

Looks like there's currently two valid coupon codes for $10 off orders over $50. Codes are 1050119 and 50129. Dunno when they expire though.

Update, 12/5/09

GunBlast has a review of American Tactical Imports (ATI) T-14 .410 AR-15 Shotgun Upper, which I mentioned back in July. It looks like Mr. Quinn was using the 13-round magazine, so they must be available somewhere in the U.S.

Also from GunBlast, a review of the Taurus TCP .380 pocket pistol, which I mentioned back in July. I kind of forgot about that pistol. I still don't think I've ever seen one in person. Unlike some other similar pistols, the Taurus locks open after the last round, and the pistol reviewed had a trigger pull that measured around 4 pounds (compared to the usual trigger pull of around 8 pounds). This one might be interesting.

I gave up trying to fix the M&P, and had the shop send it back to S&W for warranty work.

Got another Millet DMS-1 Scope from Midway to replace the dented one. As soon as I can get my hands on a American Defense Manufacturing Recon-X scope mount, I'll get to testing the scope and mount. I made sort of an interesting observation while fiddling with it, that with the power ring set to 1x, the scope actually seems to make things look smaller. True 1x seems to be somewhere between the 1x and 1.5x markings on the power ring.

I still have a couple or few reviews to post. Should have them put up by next weekend.

Midwest Industries MCTAR-08HD Front Sling Swivel

MI Part: MCTAR-08HD

I went with the heavy-duty MI quick-detach sling mount over the others after reading the Military Morons review which stated that the heavy-duty model had stops that keep the sling from twisting. The mount itself has stops that limit the sling swivel from making more than a quarter turn. I like this feature a lot, and I wish all QD sling sockets had this feature.

The mount is a fairly simple device. There are two pieces held together with an Allen-head socket screw. It works on my MI railed tube, obviously, which has rails that are a little oversized, but it also fits true 1913 Picatinny spec rails.

The only thing I feel the need to warn you about is that the screw will probably scratch the finish on the rail you mount it to. The screw threads left marks on my handguard. It’s not a big deal to me. The handguard wasn’t expensive, and the marks are covered with either accessories or ladder rail covers. If you were trying to sell an expensive firearm with integral rails, it might become an issue though.