300 BLK Under gassed?

[bwaites]

Every 300BLK I've seen is under gassed from the barrel maker. Remember it's supposed to be a suppressed round and everyone seems to drill the port like that's all it's going to do.

I've never seen one run right with subsonic ammo and no suppressor unless you drill the port.

I think the standard should be a .120 port and an adjustable block, but then I'm just a garage AR plumber!

[stanprophet]

Good info, had the same issue with my 300BO 16" Carbine Gas I too got from JSE. I asked the same question on the Thread "Ammo Available at PF" but not this good reply of info. I'll see if that is the size of my port and just open it up, guess it cant hurt. If it cycles to hard, then I'll just use a adjustable GB.

Hope it doesn't have to do with the cold so if it needs to be used I won't have to tell the bad guy to come back in the spring

Thanks stanprophet!!!

Tedward,
Was that the Stainless barrel for $135.00?

If it is I think you are going to find the port to be .093-.094. A 3/32 drill bit will just fit into the hole. We are 3 for 3 on being under gassed. That is ok, others have had the same problem with barrels that are 3 times as expensive. Let us know on the accuracy, we are truly impressed with our so far, and will of course get some better testing when the ports are drilled. We are going to run a test run with my dads Saturday morning with the port at .113. We are going to test our 150gr loads since they were noticeably lighter than the factory hornady. If they cycle then that is were we are going to drill the wife's rifle and then test her's. The load we are using is right in the middle of the road according the 9th edition of the Hornady manual. While this thing is no Grendel, it is pretty cool. Some guys are trying to compare it to the 6.8, I think it is kind of crazy to do that. It has a place, short range, hard hitting. Perfect hog and deer gun for heavy brush and wooded area's. Anyways I will update this thread when we have a definitive answer on a good cycling port size. As far as the cold, we were shooting in 65 degree weather so not a factor. Although temperature stability may be a factor on the powder used, I think once the gas problem is worked out it should be good to go.

bwaites,
I think one would be safe to drill .120 or .125. The article that LRRPF52 posted their test barrel was .110 and was able to cycle supers normal and subs with a can. they had to increase the port to .125 to cycle in all 4 configurations. They were also running a heavy buffer in their lower. As far as an adjustable gas block, I really think it can be very effective without one. Keeping the gas port around .110 it will run good with supers, subs with can, and supers with can. At .125 it will run all 4, with some over gas on supers suppressed. But I do not think it would be enough to justify an adjustable gas block. But I think it would be pretty cool to be able to turn off the gas with suppressed subs. One of the guys at the range this weekend had a 16" whisper with a 308 can, and the subs out of that thing was "Hollywood" quiet. Some action noise, but the impact of the 30cal hitting the impact area was louder than the rifle.

The thing that gets me with these barrel makers, how many times have you seen a carbine length 556 over gassed?

It is really hard to over gas the 300, so why not just drill them at .120 and call it a day?

Just like with anything else it will have its growing pains.

[Tedward]

Tedward,
Was that the Stainless barrel for $135.00? Yes

If it is I think you are going to find the port to be .093-.094. A 3/32 drill bit will just fit into the hole. We are going to run a test run with my dads Saturday morning with the port at .113. We are going to test our 150gr loads since they were noticeably lighter than the factory hornady. If they cycle then that is were we are going to drill the wife's rifle and then test her's. The load we are using is right in the middle of the road according the 9th edition of the Hornady manual. I have 3 weights too, so that is right in my range for testing.

I think one would be safe to drill .120 or .125. So that equates to an 1/8", right?

Thanks for the info. I plan to work on mine this weekend, about the only time to get some work and shooting in lately.

I also am getting ready to order a can. I want to use it for my BO and Grendel. Is the 30cal effective enough on the Grendel to go that route? Or can you change baffles when using the Grendel? Of course the seller wants you to buy one of each but I don't find that feasible.

[stanprophet]

Thanks for the info. I plan to work on mine this weekend, about the only time to get some work and shooting in lately.

I also am getting ready to order a can. I want to use it for my BO and Grendel. Is the 30cal effective enough on the Grendel to go that route? Or can you change baffles when using the Grendel? Of course the seller wants you to buy one of each but I don't find that feasible.

Ok, the barrel is made by Red-X, I have already contact him with our findings. If I get a response I will let you know.I pretty much told him that I am impressed with the quality of the barrel, but a bunch of us are under gassed. I also ordered a 20" 556 bull barrel from him for another build. More or less an FYI, and not really a complaint. Yes the .125 is 1/8, but if you plan on running a can then I think it would be best to not drill it too big. We are also using Precision drill bits to drill the holes, not a standard drill bit. The 30cal can should work fine on the Grendel, the biggest thing to worry about is proper stabilization for the ammo you are going to be running, and that the threads and thread adapter is cut concentric to the bore. With the Grendel you have some extra clearance. Most suppressors give a 40-50 thousands clearance on the baffles. So most 30 cal cans will have a .340-.350 bore. The grendel being .264 I think you are ok as far as runout.

I am not a gun smith or 07 sot FFL, but I have a design on a nice can I would love to build on a Form 1 eventually. Need a bigger place and a nice lathe first. As far as Baffles... Extra baffles are a no go for a suppressor. Extra parts with the exception of piston parts is contra ban. Will a 30 cal suppressor work as well as once made for a 6.5, no it will not. But it will still be effective at dropping the muzzle blast down.

[stanprophet]

Just an update:

Well, we drilled all 3 rifles to .113 this morning and ran down to the Farm to do some testing. We ran our reloads and got them to eject, but did not pickup the next round. We tried the Hornady 110 Vmax, and it ran fine. We then switched over to some 125 remington factory loads and it would eject, but pickup the next round in the center of the case. It would also catch the bolt on the carrier on the last round.

So we ran back home and went ahead and drilled them to .120. On the return to the field we ran some of out reloads and they were running the same as the remingtons were at .113. The remingtons ran perfect, with last round hold open working flawless. The ejection was also good with the ejection pattern around 3 o-clock.

One of the guys on the 300 forum brought up the fact that our loads were well under the starting load according to Hodgdon. They list the starting load at 16.5gr of IMR 4227 with a 150gr projectile. Hornady lists the starting load around 12gr and a max load of 16.3gr. From our findings I think Hodgdon has the info correct.

So we now have all 3 rifles running good on factory ammo, but still have some under powerd reloads. So we started to pull all the bullets and recharge a small batch of 16.0gr of IMR 4227. We are going to go back out in the morning and run a couple of the loads to check function and check for any pressure signs.

So far we are impressed with this little cartridge. Also had a chance to scope out what is going on out in the field. No Hog signs, but a bunch of sign of Coyotes. They are also staring to move in. Time to try out some of these 123gr SST's that came in, and the electronic call.

[stanprophet]

Ran a test at 16.0gr of IMR 4227 today. All rounds fired with good extraction, and loaded the next round. On the last round 1 rifle locked the bolt back by the bolt carrier, not the bolt face. The other one failed to lock back on the last round. We bumped the load up to starting load of 16.5 grains, and decided to seat a bit deeper and moved the C.O.A.L. from 2.165 to 2.150 to bring the case neck into the cannular a bit more. So far it is a success getting these rifles running. And really goes to show that these rifles need all the gas they can get. The port pressure is very low on this caliber, and they run on the ragged edge of short stroking.

Would really like to see the OP come back to the thread and see if he can get this problem resolved.