Ok so my 300aac gun does not run....

[inline 6]

I went out with phaux over the weekend to try out my new suppressor. Since I had not shot the gun at all to this point I wanted to put a few rounds through it and to dial in the gas block. Well the rifle will not cycle at all even with the gas block adjustment opened up all the way. When I installed the gas block I tried very hard to get the holes aligned as good as I possibly could and the only way I could do this was to blow air in the barrel with the other end plugged and gauge by sound and feel while I was adjusting the block around to where it felt like the most air was passing through. Otherwise the setup is a 300aac 7.5" upper form redx, a T1 or (H1) buffer which is a light weight buffer, standard spring, and a lightened carrier. The ammo I was attempting to shoot was 208gr fmj subsonic reloads. I do not know the specifics on the powder etc... Where do you guys think I should start?

[Pokulski-Blatz]

DI or piston gun?

[CJ]

What kind of ammo was this? 208gr is right on the edge of what will or won't cycle subsonic. Of course it all depends on the barrel and gas port, but my experience is 190gr won't cycle period. Sometimes I can get 208's to cycle, sometimes I can't. 220+ is usually a guaranteed thing. If these were hand loaded you need to put it in front of a chrono and make sure it's squeezing all the pressure you can. It's a lot more susceptible when they are lower weights like that. A 220 gr will cycle as slow as 850fps on the other hand.

[CJ]

DI or piston gun?

If he's blowing air through the gun it's a DI system

[Pokulski-Blatz]

If he's blowing air through the gun it's a DI system

Fair enough, the adjustable block threw me.

[inline 6]

The projectiles are Hornady 208gr amax. I don't know squat else about the rest of the ammo. I bought it from a place that does reloads and sells on GB.

Do you think with the suppressor on that it will make it cycle ?

[CJ]

The projectiles are Hornady 208gr amax. I don't know squat else about the rest of the ammo. I bought it from a place that does reloads and sells on GB.

Do you think with the suppressor on that it will make it cycle ?

I can't say for sure, didn't you just say it didn't cycle with the can? I would first try some proper 220gr subsonic loads that are chrono'd properly before tearing into that gun.

[CJ]

I can't say for sure, didn't you just say it didn't cycle with the can? I would first try some proper 220gr subsonic loads that are chrono'd properly before tearing into that gun.

shorter barrel guns have the luxury of running higher pressure cartridges because they have shorter lengths, and therefore have less velocity to keep them subsonic. Most all of the subsonic store bought stuff you will find is meant for longer barrels. With 220gr it really won't matter, it should work with both. 208 is on the line where it may not. They are going to dial it for a 16" .300blk gun because that's what 80% of people are going to have. So in a shorter barrel its' going to be under charged.

[inline 6]

I never tried it with the can. It would not thread on. I removed the compensator and tried it on one of phaux guns with the same thread and it threaded on fine. He then threaded my suppressor on the same gun and all was good but the suppressor would not thread onto my gun which made no sense. I am going to run a die over my threads to see if it binds up any.

[CJ]

Hmm. That's weird. Yes it should be a standard 5/8x24 muzzle. I would just send it back to red x to fix if that's the case. As for unsuppressed that's not too surprising, it being a 208gr and it has reduced pressure with no can, that's not that out of the ordinary. You won't be shooting subsonic rounds without a can so I wouldn't worry too much.

[inline 6]

Hmm. That's weird. Yes it should be a standard 5/8x24 muzzle. I would just send it back to red x to fix if that's the case. As for unsuppressed that's not too surprising, it being a 208gr and it has reduced pressure with no can, that's not that out of the ordinary. You won't be shooting subsonic rounds without a can so I wouldn't worry too much.

Ok, do you think I should wait and get my can situation sorted out to see if it will cycle with this ammo before I start looking to unload it? Also I am sure I can fix this thread issue myself in a much shorter time than sending it back. The threads look good on the barrel with no burrs or abnormalities. I need to check the major and minor diameters and see if I can find the issue. Worst case I throw it on the lathe and re-thread it. Either way I trust my machine work more than I do others.

[FATHERFORD]

With the can it should cycle.

[CJ]

Ok, do you think I should wait and get my can situation sorted out to see if it will cycle with this ammo before I start looking to unload it? Also I am sure I can fix this thread issue myself in a much shorter time than sending it back. The threads look good on the barrel with no burrs or abnormalities. I need to check the major and minor diameters and see if I can find the issue. Worst case I throw it on the lathe and re-thread it. Either way I trust my machine work more than I do others.

It's just hate having to work on something you paid someone else to do. I'm the kind that would fix it also, but only if I badly needed it done. If not I'd just send it back. I wouldn't worry about the problem you're having, that's easily remedied.

[inline 6]

I just went back to the boxes that the ammo came in and it is stated on the side "1078 fps" I am guessing the averaged their chronos on this load with this projectile? Either way does that change anything?

[CJ]

I just went back to the boxes that the ammo came in and it is stated on the side "1078 fps" I am guessing the averaged their chronos on this load with this projectile? Either way does that change anything?

I'm sure that's with a 16" barrel.