End Cap (Not Baffle) Strike!!!

[Squaregrouper]

Today I took my first suppressor build to AGC and couldn't hit paper at 25yds. I only fired 20 rounds suppressed until I realized something was wrong. After removing the can (oven mitt) I allowed it to cool and noticed that the end cap had been hit by a bullet(s). Once home, I took it apart and all of the FP baffles were in perfect condition. I don't know why the end cap would have been hit but not the baffles.
Stuff:
SD Tactical 9.6" titanium tube, Aluminum end cap and thread adapter. 45* freeze plugs and stainless blast chamber and spacers
PSA SBR 5.56mm with a 10.5" barrel with 1/7 twist
Perfecta .223 factory ammo
SBR w/suppressor mounted visually had a clear path and I confirmed with an acrylic rod.

Any idea what may have gone wrong?

Kyle/Squaregrouper

PS- The decibel reduction was impressive and I got to meet Melnic

 

[Fox123]

if the hole is drilled exactly in the center of the cap (prob first place I would look) or the threads on either the cap or the tube are not concentric to the hole.

 

[Melnic]

Squaregrouper, good to meet you today at AGC.
I was wondering if you checked the centering of the hole?

One thought as said was centering of the hole. With mine, I took a caliper and measured from the edge of the inside of the hole to the outside. I made my way around the hole making sure I did not have any spot that was larger than the rest. In my case I did have it a tad off center as sometimes the drill bit will walk even on a drill press if the cap is not held down well. I opened up that one thick side.

Also, what diameter hole are you using (mine is sized for 30 cal so its oversized for a 223 that I used today)

POST a PIC!

 

[fred333]

if the hole is drilled exactly in the center of the cap (prob first place I would look) or the threads on either the cap or the tube are not concentric to the hole.

Ditto.
Unless the cylinder's bent or misshapen, the end cap must be misaligned or off-center. This presumes that you're not mistaking a dent or something else for a bullet strike (not questioning your diligence, just trying to be thorough).

 

[Sundazes]

Pic?

 

[clandestine]

Im going to throw out some advice. It does not mean that Im assuming that you are a newb or anything. Just offering advice.

It might not be the can. It can be that ammo or the barrel.

Did you ensure the barrel stabilized bullets from that particular ammo before using the can on it?

You should check every barrel with a Geissele Suppressor Alignment Gauge. THat rod will probably not give a good reading. You can not ever assume a barrel has a good crush shoulder or that the threads are concentric to the bore.

Im glad to hear that just your endcap was damaged.

 

[Squaregrouper]

Im going to throw out some advice. It does not mean that Im assuming that you are a newb or anything. Just offering advice.

It might not be the can. It can be that ammo or the barrel.

Did you ensure the barrel stabilized bullets from that particular ammo before using the can on it?

You should check every barrel with a Geissele Suppressor Alignment Gauge. THat rod will probably not give a good reading. You can not ever assume a barrel has a good crush shoulder or that the threads are concentric to the bore.

Im glad to hear that just your endcap was damaged.

Im going to throw out some advice. It does not mean that Im assuming that you are a newb or anything. Just offering advice. To suppressors, I'm a complete newbie.

It might not be the can. It can be that ammo or the barrel.

Did you ensure the barrel stabilized bullets from that particular ammo before using the can on it? No

You should check every barrel with a Geissele Suppressor Alignment Gauge. You can not ever assume a barrel has a good crush shoulder or that the threads are concentric to the bore.

Im glad to hear that just your endcap was damaged. I'm thankful I went with an aluminum endcap

 

[clandestine]

Whenever you shoot a new load or factory brand you should put a target about 25 yards out and fire without the can. If the holes in the target are keyholing then you know not to use the can until you fogure out the cause. If can be failure to stabilize the projectile, damaged crown, the ammo, or jacket separation.

Pulled projectiles are really bad to use on a can because jacket separation is more likely.

 

[Squaregrouper]

I did not take pics but Melnic will confirm there were obvious signs on the endcap of bullet(s) coming outward from the suppressor. I opened up the endcap hole to 3/8" with a step drill on my drill press because I can't legally replace the endcap.
The endcap was step drilled to 9/32" (~.28 caliber). I assumed SD Tactical's center mark was an accurate place to drill the initial 1/8" hole. The baffles were step drilled @ 9/32" starting with SD Tactical's centering tool.
I will check the centering of the endcap and report back.

 

[SCARCQB]

You should always fire your gun at a 5 yard target before you screw on or attach a can. Make sure your ammo doesn't keyhole. Check the bullet holes. Make sure they are perfectly round.

 

[Squaregrouper]

Whenever you shoot a new load or factory brand you should put a target about 25 yards out and fire without the can. If the holes in the target are keyholing then you know not to use the can until you fogure out the cause. If can be failure to stabilize the projectile, damaged crown, the ammo, or jacket separation.

Pulled projectiles are really bad to use on a can because jacket separation is more likely.

I fired 5 rounds just before screwing on the can and had a 1.5" grouping @ 25yds. Low right, but acceptable grouping and no keyholing. I read about POI shift and wanted to get a feel for what it would be.

 

[clandestine]

I did not take pics but Melnic will confirm there were obvious signs on the endcap of bullet(s) coming outward from the suppressor. I opened up the endcap hole to 3/8" with a step drill on my drill press because I can't legally replace the endcap.
The endcap was step drilled to 9/32" (~.28 caliber). I assumed SD Tactical's center mark was an accurate place to drill the initial 1/8" hole. The baffles were step drilled @ 9/32" starting with SD Tactical's centering tool.
I will check the centering of the endcap and report back.

Is that a new ruling on suppressors? Unless ATF changed something the manufacturer (You) could replace any parts that are damaged except the tube (When you are the manufacturer)

 

[clandestine]

I fired 5 rounds just before screwing on the can and had a 1.5" grouping @ 25yds. Low right, but acceptable grouping and no keyholing. I read about POI shift and wanted to get a feel for what it would be.

Sounds like its the can then, or the threads/shoulder

 

[Squaregrouper]

Endcap is <1/50"/.02 caliber of being perfectly centered. I used the same step bit to open it up as I did previously, so I don't think that could have been the problem with the original ~.28 caliber hole.
I'm still confused how the baffle against the endcap was fine (same diameter), yet the endcap itself was hit.

 

[GottaEat]

I had an issue with almost the same sdtac setup. Except more baffel strikes along with the end The barrel had the sdta muzzle brake and the can threaded onto that. After it got hot the can would loosen up, and would loosen up every 2-3 shots after retightening. Realized after it was too late that hand tight with this muzzle brake/ can setup was not enough.

 

[Squaregrouper]

Is that a new ruling on suppressors? Unless ATF changed something the manufacturer (You) could replace any parts that are damaged except the tube (When you are the manufacturer)

It is my understanding that Form 1 cans are not the same as commercial cans. IE: no changing baffles, thread adapters, etc.

 

[Squaregrouper]

I had an issue with almost the same sdtac setup. Except more baffel strikes along with the end The barrel had the sdta muzzle brake and the can threaded onto that. After it got hot the can would loosen up, and would loosen up every 2-3 shots after retightening. Realized after it was too late that hand tight with this muzzle brake/ can setup was not enough.

You might be on to something.
I tried real hard to bottom out the ends when assembling and after 20rds, there was definite rattling internally when I shook the can. Not sure if the threads or internals loosened up.

 

[outrider58]

I had an issue with almost the same sdtac setup. Except more baffel strikes along with the end The barrel had the sdta muzzle brake and the can threaded onto that. After it got hot the can would loosen up, and would loosen up every 2-3 shots after retightening. Realized after it was too late that hand tight with this muzzle brake/ can setup was not enough.

A left hand threading would probably help this, but I don't know how doable the would be with a home-made can.

 

[Boss94]

It is my understanding that Form 1 cans are not the same as commercial cans. IE: no changing baffles, thread adapters, etc.

Form 1 is the same as a form 4 supressor . You can change everything but the serialized tube at any time for any reason.

 

[rico903]

Im going to throw out some advice. It does not mean that Im assuming that you are a newb or anything. Just offering advice.

It might not be the can. It can be that ammo or the barrel.

Did you ensure the barrel stabilized bullets from that particular ammo before using the can on it?

You should check every barrel with a Geissele Suppressor Alignment Gauge. THat rod will probably not give a good reading. You can not ever assume a barrel has a good crush shoulder or that the threads are concentric to the bore.

Im glad to hear that just your endcap was damaged.

Will this gauge work on bolt and AR style rifles?