10.5" Pistol Feeding Malfunction

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dpete
Silent But Deadly
Posts: 263
Joined: Thu Mar 13, 2014 8:54 pm
Location: Northern WI

10.5" Pistol Feeding Malfunction

Post by dpete »

My Son's BLK pistol has come up with an odd feeding failure. The 2nd to last bullet in virtually any magazine used will hang in the feed ramps with its nose buried into the top of the chamber entrance and the bolt wedged into the top of the case.
Image



After the jam. Pull the bolt back, drop the mag, jammed bullet drops out, reload bullet into mag, slap the mag back into the gun, release the bolt, and it fires the previously jammed bullet and the last one in the magazine as it should. It has done it once on the 3rd to last bullet, and it has done it using 30 round Pmags, 30 round colt mags, and 5 round ASC mags. You can run a 30 round mag as fast as you can pull the trigger and it fires perfectly until you get to that 2nd to last bullet.

I have rounded the edges of the ejector before trying the 3 different mags and the malf continued.

I just finished weighing and measuring the buffer system parts of this BLK and my 8" pistol that works perfectly. Tossing in weights of buffers of two other working guns. The 16" BLK that works has the same buffer system as the 10.5" malfing gun.

10.5" malfing gun..................................8" working gun.....................16" BLK working...............16" Colt Carbine

4.6 oz................buffer weight.................2.8 oz............................4.6 oz............................3.75 oz

10"...................spring length.................10.5"

34......................# of coils......................37

.071"....................wire dia.....................074"



My first thought after taking weights and measurements is this thing has too much buffer weight for the spring that is trying to push it. I plan on doing a spring/buffer swap using the 2.8 oz buffer and 10.5" spring out of my 8" pistol and see what happens.

Bullets used were 110 gr Nosler Varmageddons loaded over 19.0 gr of Lil'gun to 2.060", in a WCC cut and formed case and CCI 400 primer. They have been universally accurate and functional in 4 different 300BLK rifles so far.

Am I on the right track? Any advice would be appreciated.
dpete
Silent But Deadly
Posts: 263
Joined: Thu Mar 13, 2014 8:54 pm
Location: Northern WI

Re: 10.5" Pistol Feeding Malfunction

Post by dpete »

I just got back from the range. Thank God its only 10 minutes away. I put the spring and buffer from my working pistol into my Son's gun. Same malf with both 30 round Pmags and a 30 round Colt steel mag. The 5 round steel ASC mag fed fine with no feeding issues at all. Next step is to take some weight out of the 4.6 oz buffer and see if it will run with the original spring.

I'm also considering the possibility that the bullet length isn't agreeing with the gun for some reason. I've got some 110 gr Barnes Tac-Tx loaded up for hunting and I'll try those next.
dpete
Silent But Deadly
Posts: 263
Joined: Thu Mar 13, 2014 8:54 pm
Location: Northern WI

Re: 10.5" Pistol Feeding Malfunction

Post by dpete »

Original buffer is fubar. Steel weights that act as if they were pressed in. No way they are coming out. Ran the 110 Barnes Tac-Tx through it this afternoon. They ran in the ASC 5 rounder and jammed in the 30 rd Pmag. This was with the spring and 2.8 oz buffer from my working 300 BLK pistol.
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