Frangible damaging commercial steel?

[Erick Gelhaus]

(Feel free to move this is its in the wrong place)

Damage to steel from frangible? This is commercially built, not something from Uncle Elmer’s machine shop. We’ve have had it for several years.

Can’t recall having seen anything like this when we shot .40SW. We switched to 9mm in mid-2014. This type of damage has only appeared within the last few months.

Those who might shoot rifles with frangible rounds in there deny that they are doing it.

We just completed a yearly perishable skills training cycle where the plate rack was used weekly, shot by most every deputy in the Office. (Yes, I know, there are people mashing the crap out of their triggers … we’re working on that)

The ammunition is Speer Lawman’s frangible round, 100gr, which we chronographed at 1300fps. That is 50fps faster than our old .40SW frangible loads.

If it isn’t visible in the pictures, we are getting cuts, dents in the steel that match the shape & depth of the projectiles. There is an edge hit that is a complete penetration of the steel. The dents are deep enough that you can feel and see them on the backside of the steel. Distance has been as short as 7 yards but 10 yards is common.

Thoughts on what is causing this? MP-5s with frangible?
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[Hambo]

The only time I've seen that is with steel that was shot to shit, or when it's been shot with something it's not rated for.

[Jay Cunningham]

Frangible 5.56mm will in fact leave pin prick dimples in even the hardest steel. We're talking inside 25 yards here.

[Luke]

I've got many a round on steel with 9mm 115 grain JHP moving st 1500FPS.. never seen any damage in the slightest. Unless you've witnessed the damage I'd bet good money somebody's shooting their rifle at it.

[EricP]

16350

This is the same plate rack. All the damage has been from rifle rounds.

[GuanoLoco]

"Commercial Steel" doen't mean squat. AR400 steel or AR500 steel?

[Redhat]

OP, Do you guys use a metal bullet trap type backstop? If so, is it being damaged as well?

[GuanoLoco]

Also, if you are getting dents in the back of your steel plates, they are either soft or really thin or something...

AR500 in 3/8"+ should be fine with any pistol, open gun, or pistol caliber carbine velocities (I am thinking to 1600 fps or so).

If you aren't using at least 3/8" AR500 then you need to really manage pistol velocities and maybe even mass.

[Erick Gelhaus]

A couple of the photos show the backstop / impact area. It is shredded tire rubber. For reasons not worth diving into here, this is a frangible only range - no live ammo is supposed to be there.

We haven't had issues shooting that with frangible previously. Up until 2014, it saw a pretty decent amount of .40 and .45ACP and then limited amounts of 9mm & .38Spl. Now it almost exclusively sees 9mm.

The rack was made by a reputable company. I have a name in mind but until I hear confirmation back, I'll stick with it's comercially built, from a reputable company, not Uncle Elmer's machine shop.

The plates aen't showing anything beyond very minimal dimpling, very minimal.

Luke, EricP - thank you.

[Erick Gelhaus]

This is the same plate rack. All the damage has been from rifle rounds.

I really appreciate you posting that information and photo. Damn near the exact same damage on a near identical, if not identical, rack.

My thought has been rifle at too close distances coupled with guys forgetting their off-sets. However, the instructors on SWAT keep denying that any of their guys have shot the plate rack with their 416s. I'd wondered if the increased bbl length and resultant MV of a MP-5 could do that but EricP's picture suggests they are not the source of the issue.

[SecondsCount]

Those are rifle rounds, probably 223. You'll never get that kind of focused energy from a 9mm.

[JustOneGun]

I agree with above. Usual problems is some yahoo shooting rifle at pistol steel. We had to lock up all our pistol steel when we were gone.

Second is that old steel gets thinned out until it isn't rated the same anymore.

Of course 9mm is smaller than and faster than the 40. More force in less space. We've seen frangible punch holes right through the steel pillars of our shoot house. So maybe the steel wasn't rated for it?

[GJM]

Shooting PCC the past five months, I have noticed that 9mm at faster velocities than out of the pistols, has been hard on our MGM eight inch steel challenge plates and the hangars. Just had to order more of each.

[Erick Gelhaus]

Shooting PCC the past five months, I have noticed that 9mm at faster velocities than out of the pistols, has been hard on our MGM eight inch steel challenge plates and the hangars. Just had to order more of each.

GJM - are you seeing this kind of damage being done to your steel?

BTW, this is a MGM product.

[GJM]

GJM - are you seeing this kind of damage being done to your steel?

BTW, this is a MGM product.

I will try to take some pictures of the plates tomorrow. As the hangars break, we toss them, so they are no longer around. The steel challenge targets we use, utilize a wood 2x4 post, so they obviously get shot up over time.

Ten yards is the minimum I shoot steel with the PCC, and most often at further distances.

[Hambo]

I'd wondered if the increased bbl length and resultant MV of a MP-5 could do that but EricP's picture suggests they are not the source of the issue.

MP5 barrels are less than 9" so I don't think you'll see a huge increase in MV. We shot the same steel with 9mm pistols and MP5s without issue.

[1slow]

I use mainly MGM steel and have shot it a lot with 7.62 x 39 and a huge amount with a FAL in 7.62 x 51.

After very heavy (thousands of rounds) use with the FAL, some within 25 yards, I would get some cracks around bolt holes on bigger targets have the head crack off of mini (about 14'') poppers. MGM held up better than Blackwater steel. Hits on the very edge with FAL would take a scallop out sometimes.

The only time I have seen dimpling like you show is 5.56 x 45.

[Chuck Whitlock]

I'm out of my lane, but is the damage to the rail/rack and not the targets themselves? Could the rail/rack be made from lesser grade material?

[Backspin]

The rack stand is most certainly made of less hardened steel than the targets themselves.

Angus, we have MGM plate racks at my place and we shoot .357 sig, which is practically a 125 gr. 9mm round going 1300 FPS. .357 sig doesn't damage the rack stands like that.

But we had 2 rack stands (both less than one month on the range) cratered like yours due to someone shooting what we assume to be rifle rounds wayyyy to close (we assume because no one ever fessed up to the damage...whoever it was it was a fellow cop...). We believe it was .308 or perhaps green tip that did the damage because we had a hole burned clean through one of the target plates as well.

[GuanoLoco]

The rack stand is most certainly made of less hardened steel than the targets themselves.

Angus, we have MGM plate racks at my place and we shoot .357 sig, which is practically a 125 gr. 9mm round going 1300 FPS. .357 sig doesn't damage the rack stands like that.

But we had 2 rack stands (both less than one month on the range) cratered like yours due to someone shooting what we assume to be rifle rounds wayyyy to close (we assume because no one ever fessed up to the damage...whoever it was it was a fellow cop...). We believe it was .308 or perhaps green tip that did the damage because we had a hole burned clean through one of the target plates as well.

More likely 5.56, M193 or maybe Q3131 or something fairly hot along those lines. I have clocked Federal XM193 from a 16" AR-15 barrel at 3200 fps and it WILL zip right through most pistol plates at short range. 308 is heaver and slower and LESS likely to do damage from speed/heat, although the impact can be impressive and might cause warping of the plate.

[PPGMD]

I was browsing MGM's site, and it seems even their plate rack uses lesser steel on that part. They sell a special guard to put over the rack to protect it from rifle fire.

https://mgmtargets.com/plate-racks-dueling-trees/ar-rifle-shield-for-mgm-plate-rack

They also make one for Bianchi spacing.