Hi,
About 2 years ago I bought a custom built AR in 7.62x39mm Piston Driven. The description from the seller is at the end along with some pictures.
I am having two problems with the rifle.
First is a feed problem. I have tried FMJ, JHP and SP. The first time I shot it I used the FMJ and JHP in 122gr. They feed about 95+%. The second time I tried SP in 154gr (All were Wolf ammo). The SP FAILED about 95+% and the weapon would feed the JHP about 40% of the time. I have attached a photo of the bullet and you can see the nose is messed up. The chamber has two ramps leading up to it. It looks like the bullets hit the outside side of the ramp and stop. I contacted the Magazine Manufature ASC and the said that they would replace the magazines. They were new when I got them. My question is should I try to polish (they look smooth and clean) and enlarge the ramps? or get replacement magazines to see it that helps? or should I polish the ramps and try to modify the magazines a little. The modification would consist on loosing the lips and lowering the front of the magazine a little.
The second problem is that 122 gr bullets tumble. I have shot targets at 30 yard and you get a profile of the bullet not a round hole. With the few 154 gr bullets I have shot so few that I haven’t seen what they do to the target.
The builder told me to contact the barrel manufacture. I contacted Shaw about the tumbling and they said that they made barrel blanks not finished barrels for the AR and were no help. Hopefully the heavier bullet won’t tumble.
The builder said to get a new barrel or change the cal and buy a new barrel and BCG to solve the problem with the tumbling.
I am not sure that I would tackle changing a barrel. The rifle used a piston system.
Any ideas would be appreciated. As always money is a problem. I started a new job 4 days ago and I have already got a day off without pay.
Thanks,
Jeffrey
 
Custom Made Smith and Wesson 7.62x39 Piston AR rifle.
Smith and Wesson Lower with Magpul MOE Stock with heavy buffer 7.62x39 16" M4 style barrel, Piston Gas System Upper/Bolt Carrier.
Auto Bolt Carrier with 7.62x39 bolt
Ambidextrous sling hooksCustom fit VLTOR CASV-EL Quadrail Handguard
Magpul B.A.D. Lever
2 - 30 Round ASC Metal 7.62x39 Magazines with Army Mag Clamp Kit with Magpul rubber magazine puller.
Barrel is made in America ER Shaw 7.62x39 heavy Chromoly barrel with a 1/10 twist and A2 style bircage flash hider
Using the proper grain bullets recommended for target shooting and hunting.
This build has less than 100 rounds through it.
It has been used only to function test the Piston/Barrel/Handguard combo.
This rifle is very accurate with superior knock-down power, and very little kick.
You will have a lot of fun shooting it.
About 2 years ago I bought a custom built AR in 7.62x39mm Piston Driven. The description from the seller is at the end along with some pictures.
I am having two problems with the rifle.
First is a feed problem. I have tried FMJ, JHP and SP. The first time I shot it I used the FMJ and JHP in 122gr. They feed about 95+%. The second time I tried SP in 154gr (All were Wolf ammo). The SP FAILED about 95+% and the weapon would feed the JHP about 40% of the time. I have attached a photo of the bullet and you can see the nose is messed up. The chamber has two ramps leading up to it. It looks like the bullets hit the outside side of the ramp and stop. I contacted the Magazine Manufature ASC and the said that they would replace the magazines. They were new when I got them. My question is should I try to polish (they look smooth and clean) and enlarge the ramps? or get replacement magazines to see it that helps? or should I polish the ramps and try to modify the magazines a little. The modification would consist on loosing the lips and lowering the front of the magazine a little.
The second problem is that 122 gr bullets tumble. I have shot targets at 30 yard and you get a profile of the bullet not a round hole. With the few 154 gr bullets I have shot so few that I haven’t seen what they do to the target.
The builder told me to contact the barrel manufacture. I contacted Shaw about the tumbling and they said that they made barrel blanks not finished barrels for the AR and were no help. Hopefully the heavier bullet won’t tumble.
The builder said to get a new barrel or change the cal and buy a new barrel and BCG to solve the problem with the tumbling.
I am not sure that I would tackle changing a barrel. The rifle used a piston system.
Any ideas would be appreciated. As always money is a problem. I started a new job 4 days ago and I have already got a day off without pay.
Thanks,
Jeffrey
 
Custom Made Smith and Wesson 7.62x39 Piston AR rifle.
Smith and Wesson Lower with Magpul MOE Stock with heavy buffer 7.62x39 16" M4 style barrel, Piston Gas System Upper/Bolt Carrier.
Auto Bolt Carrier with 7.62x39 bolt
Ambidextrous sling hooksCustom fit VLTOR CASV-EL Quadrail Handguard
Magpul B.A.D. Lever
2 - 30 Round ASC Metal 7.62x39 Magazines with Army Mag Clamp Kit with Magpul rubber magazine puller.
Barrel is made in America ER Shaw 7.62x39 heavy Chromoly barrel with a 1/10 twist and A2 style bircage flash hider
Using the proper grain bullets recommended for target shooting and hunting.
This build has less than 100 rounds through it.
It has been used only to function test the Piston/Barrel/Handguard combo.
This rifle is very accurate with superior knock-down power, and very little kick.
You will have a lot of fun shooting it.