Magazine or undergassed?

armednfree · June 19, 2020, 09:22 AM

History:
I purchased a Bear Creek Arsenal 20" upper in 350 Legend. I attached that to an A1 configured lower. I only had 57 cases (Range pickups). I loaded Armscorp 147 Grain FMJ-RN ahead of 28 grains LiL' Gun and a CCI 400 primer.

Accuracy was good, but more to the point of this, cycling was normal. About 45 rounds fired with zero malfunctions.

Now:
Since I only had 57 cases and Starline was saying the end of July before my order comes in I ordered some Winchester. I ordered the 147 FMJ. I began experiencing malfunctions immediately. I loaded 3 rounds at a time of 20 rounds in a 5 round DuraMag 350 Legend magazine. The first round would strip and feed normally. The second would go bolt over brass and not feed at all, but then fed normally when the action was cycled. The third round went nose up into the barrel extension. The bolt did not lock at all except when cycled manually.

I noted that in comparison to my reloads the Winchester ammo of the same weight recoiled noticeably less.

I think what I'm seeing is an under gassed situation. Notably the factory round is not producing enough pressure to cycle the bolt.

I think an experiment would be to pull some of these factory bullet, replace the powder and taper crimp the bullet back in.

Thoughts?

stagpanther · June 19, 2020, 10:14 AM

My guess is magazine feeding issue--the factory win 145 is a bit on the shorter COL side and also really has a truncated flat nose, so my guess is your getting some pitching up of cartridge on feed, especially if the problem seems to occur around the same round count. They may be the same thing--but I use CMMG 350L mags.

armednfree · June 19, 2020, 12:24 PM

Could be. But I pulled 20 rounds. Checking 5 I found a range of charge weights of 19.6 to 19.9 grains of some light grey ball powder. It looked nothing like WW296.

Dropping 28 grains of H110 in we will see what we see.

stagpanther · June 19, 2020, 06:36 PM

Quote:

Dropping 28 grains of H110 in we will see what we see.

I tried H110 in a 350 L load and it was pretty mediocre for me--but maybe you'll get better results. I did find one stellar load using Winnie's 180 PowerPoints using 28.5 grs of 1680, COL 2.2. As with any load, carefully work you way up to that charge and watch for pressure signs.

armednfree · June 19, 2020, 08:37 PM

Data for this new round is sparse. 357 Maximum date crosses over so I'll have to look at that.

bfoosh006 · June 21, 2020, 03:42 AM

https://www.google.com/search?client...4dUDCAs&uact=5

Seems to me I have read about issues with Winc. 145gr FMJ factory loads.

stagpanther · June 21, 2020, 04:51 AM

The short throat of the 350 L is not tolerant of any "intrusion" by the case. But what REALLY is bad is the headspace tolerance of .01" (Fortunately PTG's gauges stopped at .007" with their no-go gauge.)--that might be OK for a revolver but that's asking for trouble in a rifle. I discovered early on that a manufacturers barrel could be in compliance with SAAMI specs but still result in unsupported case heads--certain cases--like starline's--could have the base of the case up to the top of the web unsupported depending on what side of the tolerances the chamber was cut. PCC's typically cut a radius into the breech face of the chamber to assist a flat-nose or "stubby" pistol bullet to feed into the chamber with increased reliability (that's what I have on the 350 L barrels I bought for AR's).

TX Nimrod · June 21, 2020, 12:55 PM

But the OP’s issue is with feeding cartridges out of the magazine which has little to do with chamber dimensions. That information is good to know though.

.

armednfree · June 23, 2020, 09:09 PM

Today I shot AA1680, the rifle ran fine. It ran fine with H110 (crappy accuracy) and with Lil' Gun. As soon as I switch to the Winchester load it does this crap. Defiantly short stroking wit that load.

Former lots reported popped primers and even case head separations. This seems like they over compensated.

Garandman3 · June 25, 2020, 06:06 PM

Armednfree:

What is the COL and bullet weight on your loads?

armednfree · June 27, 2020, 03:30 PM

Quote:

Originally Posted by Garandman3

Armednfree:

What is the COL and bullet weight on your loads?

Actually I just loaded some 180 grain Winchester SP's. The book says 2.11 but the best my dies would do is 2.17. Fed and shot great though. Then I shot some of the Winchester stuff, same old crap. I ended up single loading them.

cpa22 · June 28, 2020, 01:25 AM

try changing the recoil spring. i had this same problem with 224 valkyrie.

June 19, 2020, 09:22 AM	#1
armednfree Senior Member Join Date: October 30, 2016 Posts: 211	Magazine or undergassed? History: I purchased a Bear Creek Arsenal 20" upper in 350 Legend. I attached that to an A1 configured lower. I only had 57 cases (Range pickups). I loaded Armscorp 147 Grain FMJ-RN ahead of 28 grains LiL' Gun and a CCI 400 primer. Accuracy was good, but more to the point of this, cycling was normal. About 45 rounds fired with zero malfunctions. Now: Since I only had 57 cases and Starline was saying the end of July before my order comes in I ordered some Winchester. I ordered the 147 FMJ. I began experiencing malfunctions immediately. I loaded 3 rounds at a time of 20 rounds in a 5 round DuraMag 350 Legend magazine. The first round would strip and feed normally. The second would go bolt over brass and not feed at all, but then fed normally when the action was cycled. The third round went nose up into the barrel extension. The bolt did not lock at all except when cycled manually. I noted that in comparison to my reloads the Winchester ammo of the same weight recoiled noticeably less. I think what I'm seeing is an under gassed situation. Notably the factory round is not producing enough pressure to cycle the bolt. I think an experiment would be to pull some of these factory bullet, replace the powder and taper crimp the bullet back in. Thoughts?

June 19, 2020, 10:14 AM	#2
stagpanther Senior Member Join Date: March 2, 2014 Posts: 11,789	My guess is magazine feeding issue--the factory win 145 is a bit on the shorter COL side and also really has a truncated flat nose, so my guess is your getting some pitching up of cartridge on feed, especially if the problem seems to occur around the same round count. They may be the same thing--but I use CMMG 350L mags. __________________ "Everyone speaks gun."--Robert O'Neill *I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!*

June 21, 2020, 04:51 AM	#7
stagpanther Senior Member Join Date: March 2, 2014 Posts: 11,789	The short throat of the 350 L is not tolerant of any "intrusion" by the case. But what REALLY is bad is the headspace tolerance of .01" (Fortunately PTG's gauges stopped at .007" with their no-go gauge.)--that might be OK for a revolver but that's asking for trouble in a rifle. I discovered early on that a manufacturers barrel could be in compliance with SAAMI specs but still result in unsupported case heads--certain cases--like starline's--could have the base of the case up to the top of the web unsupported depending on what side of the tolerances the chamber was cut. PCC's typically cut a radius into the breech face of the chamber to assist a flat-nose or "stubby" pistol bullet to feed into the chamber with increased reliability (that's what I have on the 350 L barrels I bought for AR's). __________________ "Everyone speaks gun."--Robert O'Neill *I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!* Last edited by stagpanther; June 21, 2020 at 08:03 AM.

June 21, 2020, 12:55 PM	#8
TX Nimrod Senior Member Join Date: November 27, 2009 Location: Zona Posts: 423	But the OP’s issue is with feeding cartridges out of the magazine which has little to do with chamber dimensions. That information is good to know though. . __________________ .22LR - .223 - .22-250 - .243 - 6mm REM - .25-20 - .25-35 - .25 BB - .250/3000 - .257 WBY - .260 - .30 M1 - .300 BO - .30 Herrett - .300 Savage - .32 H&R - .303 - .338-06 - .338 WM - .35 REM - .38-55 - .45 LC - .45-70 - .50-70

June 19, 2020, 12:24 PM	#3
armednfree Senior Member Join Date: October 30, 2016 Posts: 211	Could be. But I pulled 20 rounds. Checking 5 I found a range of charge weights of 19.6 to 19.9 grains of some light grey ball powder. It looked nothing like WW296. Dropping 28 grains of H110 in we will see what we see.

June 19, 2020, 08:37 PM	#5
armednfree Senior Member Join Date: October 30, 2016 Posts: 211	Data for this new round is sparse. 357 Maximum date crosses over so I'll have to look at that.

June 21, 2020, 03:42 AM	#6
bfoosh006 Senior Member Join Date: February 17, 2009 Posts: 1,089	https://www.google.com/search?client...4dUDCAs&uact=5 Seems to me I have read about issues with Winc. 145gr FMJ factory loads.

June 23, 2020, 09:09 PM	#9
armednfree Senior Member Join Date: October 30, 2016 Posts: 211	Today I shot AA1680, the rifle ran fine. It ran fine with H110 (crappy accuracy) and with Lil' Gun. As soon as I switch to the Winchester load it does this crap. Defiantly short stroking wit that load. Former lots reported popped primers and even case head separations. This seems like they over compensated.

June 25, 2020, 06:06 PM	#10
Garandman3 Member Join Date: June 5, 2012 Posts: 27	Armednfree: What is the COL and bullet weight on your loads?

June 28, 2020, 01:25 AM	#12
cpa22 Junior Member Join Date: September 14, 2019 Posts: 5	try changing the recoil spring. i had this same problem with 224 valkyrie.