I shot myself!!!! (sort of)

[protohyp]

So let me just give you a run down of set up and events.

9mm AR pistol

YHM upper
CMMG 9mmBCG
Wilson 7.5" barrel
YHM comp/brake
Fortis hand guard

Basically went out to the desert to try my second owner pistol upper in 9mm. Took two shots and on the third shot felt what seemed to be a sting on my left hand that was on the hand guard. I thought it felt like dust being kicked up and didn't think much of it until I noticed blood dripping down my hand. I took a look and noticed a sharp little cut and after a little inspection realized that it was a piece of jacket had fragmented and imbedded in my left hand. It took a bit to dig it out but it was probably about a millimeter square piece of jacket. I decided to take another shot after inspecting the muzzle and didn't see any damage. Sure enough a smaller piece bit in to me again. This time upon inspecting the YHM brake I noticed a clump of grease stuck on one of the holes. I thought well I'll just pack up this rig and inspect it at home. Got the wounds cleaned up and disinfected and thought back to my last tetanus shot and remembered I'm up to date.

Anyway...got home and took a look and this is what I found



This is the build up of grease that came out of the barrel. You can hopefully see itin the picture inside one of the brake vents.



Wiped the grease on a napkin and sure enough it had pieces of jacket in it



My poor little wound..small but bled quite a bit. Luckily I had my first aid kit and tweezers to pull it out

Anyway. The previous owner said he never had an issue and before the yahoos say to blame him I fully trust the guy. The brake is threaded on correctly. But may be out of spec. Anyway...I'm gonna take it off and see what happens without it but just curious to what you guys may think. The weirdest thing is the build up of grease. Before I shot it i inspected and cleaned everything and the PO used froglube on the BCG but never saw a build up of grease anywhere. At least not the amount that had stuck itself on the comp. weird...anyway...thoughts?


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[SkyHawk]

Two thoughts
1) where did the grease come from if the pistol was inspected and cleaned before you took it to the range?

2) that is the worst setup for a business end that I have ever seen. You may as well be grabbing on to the brake when you shoot! You need a linear brake, like yesterday.

If you plan on keeping that brake and that handguard, you better invest in some kevlar+nomex gloves

[kenl]

Possibly the brake is undersizes, and meant for a .308?

[beanz2]

Did you remove the brake when cleaning it? Ask the 1st owner if he's ever used any grease on the rifle.

[Devilmonkey89]

Two thoughts
1) where did the grease come from if the pistol was inspected and cleaned before you took it to the range?

2) that is the worst setup for a business end that I have ever seen. You may as well be grabbing on to the brake when you shoot! You need a linear brake, like yesterday.

If you plan on keeping that brake and that handguard, you better invest in some kevlar+nomex gloves

+1
My 6.8 spc pistol with a brake was just like your setup, got that rail cut back 1.5" no way i was going to have my muzzle brake blast flames into my hands. The grease is really weird, only way it would come out the barrel is if it was *In the barrel or *from the install on the flash hider. Are you threads concentric? That bit of metal jacket is weird. Get a linear brake for sure.

[sealocan]

what type & brand ammo were you using?

[SkyHawk]

9mm linear comps are hard to find but should solve your problem. Try this - perhaps the only choice in 9mm: http://www.kakindustry.com/ar-15-par...-flash-can-9mm

Or the fatter one

http://www.kakindustry.com/ar-15-parts/upper-parts/barrels/barrel-parts/flash-hiders-and-muzzle-breaks/for-1-2-36-threads/kak-industry-flash-can-9mm

Either that or cut the rail back.

Check here to see what else can happen when you run a birdcage brake/hider inside a rail: http://www.m4carbine.net/showthread....lew-up-my-rail

[protohyp]

Thanks guys especially sky hawk for all that info. I do understand it's not the ideal set up and I'm sure you understand that if I grabbed the rifle at the comp the cuts would be in my palm not on the top of my hand. My hand was well back of the comp (somewhere in the middle of the guard rails about 3" back) which is the reason I was surprised. I had planned on changing the barrel to a 10.5 as to replicate all my 5.56 in 9mm but I thought why not give this thing a dance before I do so.

On the JSE website it says the comp is sized for 9mm and yes the source of the grease escapes me and obviously I missed something but if grease is the source of the jacket fragmenting then I guess stranger things could have happened.

Possibly the grease was in the comp vents already and I just missed it. It is the same color as the comp and I may have glossed over it. So in theory the grease may have just caught the fragments and may have done nothing to cause the fragmentation. So yeah I'll admit that I just cleaned the barrel and receiver and BCG and just checked at home to see if rounds loaded properly so I didn't see a reason for rounds to fragment on the way out unless that is normal which I just don't think so.

I do like the linear comp but if I end up going with a 10.5" barrel it doesn't solve the problem of figuring out why the jacket is fragmenting at the brake or even prior to that. From what I surmised the jacket bounced back after hitting one of the comp vents twice...maybe multiple times as i only got cut twice. I was using reloads but i'll call shenanigans if any bullet snobs say that is the reason right there...it may very well be. I know the comp has some serious coating on it but there is no damage or scratches from the fragments at all. There is also no damage to the inside of the rail from fragments which is the exact rail as the one that blew up in the link above.

Anyway SkyHawk thanks for the KAK links...it may be something i'll do if I don't end up changing the barrel but I most likely will be going with a 10.5 as soon as I can.

Anyone want a 7.5" wilson barrel with a really 'cool' comp???

[curtru]

I do lol. As to why you bleed like a stuffed pig there are many blood vessels and vains close to the surface. Also the angle of the cut for the brake with the grip going past it could be fragments getting shaved off hitting the guard and embedding in your hand.

[protohyp]

Got the KAK linear comp as suggested and it's awesome! May not go to a 10.5 barrel because the comp looks awesome tucked in the rail


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[SkyHawk]

Looks B.A.! Have you shot it yet - is it better?

[viet4lifeOC]

Pull a John Kerry....

Purple heart.

[protohyp]

Looks B.A.! Have you shot it yet - is it better?

Yes it's smooth as butter!


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[rkt88edmo]

Either the brake hole is too small or the threads aren't square on the brake or barrel.

Can you pass the butt end of a 9mm cartridge through? Can you caliper measure the hole?

Does a 9mm generate enough gas to provide much force through the brake?

[protohyp]

Either the brake hole is too small or the threads aren't square on the brake or barrel.

Can you pass the butt end of a 9mm cartridge through? Can you caliper measure the hole?

Does a 9mm generate enough gas to provide much force through the brake?

I didn't do any of those things because I knew that a brake like that in the hand guard was not a good idea. I only shot it to test it and never expected it to do what it did. Now I don't have to worry about it because it shoots fine.