Light primer strikes with JP AR-10 SCS

[cjlane]

Like title says, I took my MATEN out to the range to check out my new JP silent capture spring. Every few rounds or even every other round, the gun would light primer strike and not fire. If I manually feed a round and release the BCG from locked position, the round will fire every time. Does anyone know what the issue is?

Specs on the gun:
MATEN with DPMS BCG and bolt, JP SCS in a Magpul UBR.

I tried three different kinds of Ammo ranging from 147gr to 168 and they all had the same issue.

Before I got the JP SCS I had normal buffer and spring and never have a single malfunction.

Gun has about 300 rounds through it.



Thanks for the help!

 

[SeaBassHWD]

I may be wrong but I think the JP SCS is engineered to work with their LMOS system.

 

[rookie101]

make sure your firing pin channel is clean, firing pin etc. buffer and spring should just put the bcg into battery and manage recoil. another thing to look at is the hammer spring. I have put them in backwards before, FNG mistake, but it can happen if you have had the trigger group apart.

 

[cjlane]

I may be wrong but I think the JP SCS is engineered to work with their LMOS system.

It was my understanding that it can be used with standard BCGs as well?

 

[cjlane]

Ill take my BCG apart to make sure it is clean. Trigger is a SSA-E and is assembled correctly.

 

[cjlane]

BCG looked pretty clean. Any other ideas?

 

[PSYOPS]

more gas.....or less gas

I dunno.

 

[800mZero]

JP sells a spring kit to further tune the system. I would give them a call, tell them your particulars, and see which spring the recommend.

 

[BgBmBoo]

^ this.

It sounds like the BCG is not going all the way into battery. I would call JP and order their spring kit for the SCS and try a heavier spring.

 

[Kiba]

What spring is in the SCS now, specifically the coloration on each end of the spring? While JP sells a spring kit with 3 different rates I believe the AR10 SCS ships with the heaviest rate spring already installed-- at least mine did.

If the spring on your SCS has one end yellow, one end red, you already have the heaviest rate spring.

JP Rifles

Another issue I'm thinking is maybe your buffer tube or the spacer included with the SCS, when combined, is a little off and the system isn't quite long enough to keep some pressure on the back of the carrier when the bolt & carrier is fully in battery. Make sure that when the SCS is seated all the way at the back of the buffer tube that the front face is sitting just past the mid-point of the buffer retaining pin in the lower to ensure the carrier will have some pressure against it when in battery.

 

[cjlane]

What spring is in the SCS now, specifically the coloration on each end of the spring? While JP sells a spring kit with 3 different rates I believe the AR10 SCS ships with the heaviest rate spring already installed-- at least mine did.

If the spring on your SCS has one end yellow, one end red, you already have the heaviest rate spring.

JP Rifles

Another issue I'm thinking is maybe your buffer tube or the spacer included with the SCS, when combined, is a little off and the system isn't quite long enough to keep some pressure on the back of the carrier when the bolt & carrier is fully in battery. Make sure that when the SCS is seated all the way at the back of the buffer tube that the front face is sitting just past the mid-point of the buffer retaining pin in the lower to ensure the carrier will have some pressure against it when in battery.

It looks like the heaviest one. The red is easy to see but the yellow is not as obvious.