So I typically use lilgun for my .300BLK loads with 110g bullets (either round nose 30-30 bullets or Spitzer points) and mixed Remington and pmc .223 converted brass. This combo works great for me. Here recently I've had troubles finding lilgun so I've been working up loads with imr 4227. I've been having issues with failure to feeds with the low starting charges, so last night I loaded in .2 increments from 17.8 up to 19.5 max charge. I can not get the bolt to lock back on last round. I use this test to determine if the bcg is traveling rearward enough to load the next round. Anyone have any ideas what the issue may be? Load is .223 mixed pmc/remington brass, length 1.350. Bullet is hornady 110g Spitzer. Primer is 7 1/2 bench rest remingtons. Started at 17.4 of imr 4227, up to 19.5. Col 2.040.

Rig is vltor upper, dpms bcg, Wilson combat stainless 11.25in barrel and extension, pistol length gas system. Standard buffer, cut the spring down two turns in attempt to get it running. Still no luck.

I will look at my data tomorrow but I have a kick ass 110gn load with 4227.

IMR4227 is slower than lilgun by quite a bit, it's about halfway to AA1680, but it should still at least run the gun.

Cutting the recoil spring down reduces spring preload, but makes the spring stiffer overall. That will contribute to short stroking, not help it. If you want to fix it that way you need to buy spring with a lower lb-in rate.

Im curious if the fact im running a pistol length gas sytem has anything to do with it. For what its worth, the rounds i tested with were actually remington 6 1/2 primers. I know they're not supposed to be used in high pressure rounds, but at 19.4g 4227 i had no pierced primers. Besides the weaker cup they should function fine for .300BLK with 4227 right?

According to IMR you are right in the ball park. You would be hard pressed to fit any more 4227 in the case at 19.5gr. We had a problem with our first loading of 150gr FMJ with 4227 because of Hornady's load data is light. I would start checking all the basic things like gas block alignment, carrier key, make sure the bolt is lubed well. How may rounds do you have through the gun?

Getting close to 1000 now, maybe 800ish. Carrier key bolts are tight and staked. Bolt fits snug in carrier via the bolt face down and see if carrier drops test. Bcg slides smooth and easily fore and aft. I do have some carbon around where my gas tube enters my gas block. I'll get pics of that tomorrow and post.

Don't mean to step on your thread OP but I could use some help too.

The only powder I was able to find is IMR 4227 and i have no load data in my manuals.

Can someone give me some start loads with 147gr M80 pulled bullets?


Thanks

i had to use a faster burning powder in mine im now using w269 at 17.5 gr with 130 gr sp

Then you haven't tried lots of published data

Sorry I was trying to avoid having a bunch of threads going asking about the same powder.

300blktalk.com has some good reloading information

Posted on black talk as well. :( Way have to go out and find a five pounder of lilgun.

Bump

I have had luck with 17 grains pushing 125 grain .310 bullets.

Edit to add, are you using a heavy buffer?  Double edit I see you are using a standard buffer.

With an 11 inch barrel, have you thought about using a Pig break or similar style break to get more back pressure?

Running a AAC blackout for use with 762sdn6 in the near future. Side note, will an adjustable gas block flow more gas at wide open that a standard? (Ie are the ports on adjustable generally the same size as standard or bigger?

No idea on the adjustable gas.  Sorry

I have only been able to get 124gr Noslers and 150gr FMJs to work well with 4227.

During the panic I could not get any 1680 and a burn rate chart showed 4227 near the same as 1680. I bought some for subs. That did not work for me, would not cycle, went supersonic ect.

I have not tried them with 110s, some people have and have had good luck.

Not sure if this helps, but I could only find IMR 4227 for my first 300 blk loads.  My first rounds through the gun were factory Gorilla 125 SMK's.  Those rounds would cycle, but not lock back on the last round.  My first reloads were 125 SMK's ranging from 16.7 - 18.6 grains.  Data was from Sierra 5, with a low of 16.2 and max of 18.7.

I could not get full function until I reached 18.2 grains of IMR 4227.  This round cycled, fed properly and locked back on empty. Accuracy seems pretty good (see below target marked 300-4 18.2).

Specs:

FC 1x 223 brass processed to 300 blk.
trim @1.359"
CAOL:  2.21"
Crimped @10lbs with a Lee FCD - consistent crimp.
Primer was CCI 41

The rifle is a 16" Wilson 1/8 SS barrel with carbine gas.  The buffer set up is a standard spring with a Spikes T2 buffer riding in a Magpul UBR extension/stock.  I'm going to lower the buffer weight to a T1 to see if it helps cycle the lower end rounds.

I also loaded some Nosler 125 BT (green tip) at varied levels from 16 - 18 grains of IMR.  Data was from Nosler.  The higher ends would cycle, but none would lock back on empty.  The rounds were loaded the same as above, but COAL was set at 2.06".  They fed fine.  18.2 will probably get these to work, but that is over the Nosler max, while still well within the Sierra max.  I'm loading some of those tonight since none of the above mentioned rounds showed any pressure signs.

Here are the targets - 25 yards with an Aimpoint ML2 non magnified red dot.
Nosler 1st picture - Sierra SMK 2nd picture.

 

Nice thank you.

Thanks very much. We're cooking with gas now (or burning with 4227 anyways ha!) I read somewhere that If you place your bcg in your upper and it wont freely slide forward then either it is dirty or your gas key is misaligned. Cleaned everything up really well (Ive been lazy and it did need cleaned) and lubed everything real well and ran those 19.5 charged loads again and they held the bolt back fine, no issues. Ill be taking 100 round of this to the range this weekend and see how things go.

I ran another test run with 4227 and the 125 SMK's listed above.  I used a standard weight buffer instead of the T2.  That got the 18g loads to run right, but the 18.2 is still the best for accuracy and function for the SMK's.  Above 18.2 started to decline in accuracy.

I loaded some TNT 125's at 2.01" COAL, new Hornady 300 BLK brass, CCI 41"s and 4227 weights of 17.5, 18 and 18.2.  The 17.5 is a great round accuracy wise, but iffy on lock back on empty.  It is so accurate that not locking back may be worth it, although with some more playing around I am confident I can get it to function 100%.

The 18g was decent and always locked back, accuracy started to decline.  18.2 was all over the place.

I shot these at 50 yards using the Aimpoint ML2 non magnified red dot.  This is the 125 TNT, 2.01" COAL, 17.g 4227 - five shots at about .50" or 1 moa.  I'll run another test of it next time to confirm this was not a fluke (I don't shoot this well!).  The high left grouping from the POA is the result of a 25y zero using different ammo.
(ETA: On Target got .537" or 1.026 moa)


Here is the uncleaned Hornady 300 BLK brass from the above TNT 125 five shots.  See any signs of high pressure?  The red ink around the primer is just my way of marking brass to tell a specific load.  The loads in the background are the SMK's, not the TNT's

My 110g hornady Spitzer points with 19.5g imr 4227 in converted .223 cases and rem 6 1/2 primers average a nickle sized group at 75 yards. Bench rest (no bipod, me supporting rifle weight) with eotech and g33 3x magnifier. Is that any good?

YES

Thanks flash, I actually have read the notice for those specific primers. I've ran almost 500 now, and havnt had a single blown primer. Call it luck I guess. I wont be buying any more but I will be using the last 100 or so I have.

K buddy thanks.