JP Silent Capture Spring Problems...HELP

[NHPiper]

So I am getting light primer strikes when I use a JP Silent Capture Spring Gen 1 and the white plastic rifle extension that comes with it. I am wondering if the spring is too weak and isn't forcing the BCG far enough forward for the firing pin to indent the primer enough? My build specs are below...I had the same light primer strike problems with my reloads (Winchester small rifle primers) and Freedom Munitions .223. Every time a recharged the rifle to pull the hammer back for a second strike, the round went off.

RRA Varmint 20" Upper
Luth Rifle Length Buffer Kit
RRA Lower w. a Geissele trigger

I couldn't pinpoint the issue to the JPSC until I put the Luth buffer spring and buffer back in and the rifle shot fine.

Any thoughts?

 

[Graeme]

Your buffer tube may be too long?

 

[NHPiper]

I read somewhere that i might be able to fix the problem by putting a quarter or two behind the buffer.

 

[digitalshooter]

Try the quarter trick. That is what JP will recommend you try first.

 

[quicklx]

Call JP. They have excellent customer service and will help address the issue.

 

[digitalshooter]

I started having a similar issue to the OP when I started using a suppressor. JP said to either try the quarter trick or increase the weight of the SCS because I had accidentally bought the standard weight version of the SCS. Up until I started using the suppressor everything was working great and I hadn't had one issue with the rifle. When I started using the suppressor I started to get bolt bounce back because the BCG group was travelling to fast. Once I adjusted the gas block down I stopped getting the bolt bounce back. Once that stopped I started getting light primer strikes. JP said it sounded like the BCG wasn't going all the way forward and locking into position. They said to try the quarter trick if the BCG wasn't up against the SCS or increasing the weight of the SCS because it might be to light. When I tried increasing the gas up again after only a couple of clicks I started getting the bolt bounce back again so I'm thinking my issue might be that the SCS is just to light at this point to get the BCG to go all the way forward and lock when it starts to get dirty which is pretty quick with a suppressor. LOL.

So try the quarter trick and if that doesn't work then give JP a call and they will help you through it.

 

[sig2009]

I agree. Try the quarter first. I had the exact same problem and I worked it out with Dustin at JP. If the face of the capture assembly is not in full contact with the back of the bolt carrier the spring will not hit the bolt carrier hard enough and will bounce around causing the lite primer hit.You can put a piece of paper between the back of the upper and lower and see if its making good contact.
If that doesn't solve the problem then you may have to go with the heavier weights that JP sells. But as I said before they will work you through this.Also they have different spring weights to swap out the spring.

 

[NHPiper]

Thanks for all the posts. I called JP Monday afternoon and still havent heard back.....

 

[digitalshooter]

Interesting you haven't heard back. They returned my emails almost immediately.

Good thing is I think I got my rifle worked out. Got the tungsten weights yesterday, installed them onto the SCS and it seems to have done the trick. 30 rounds today without a failure of any kind without the rifle being cleaned. Now to give it a good cleaning and start doing real reliability testing.

 

[Saf3sh00t3r]

Same issue here, got heavier weights on my rig along with the heavier spring and have no issues now. Also tried the quarters...that didn't fix it.


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[mpk1996]

remember on the SCS setup, you need it more forward than a std spring and buffer would be. that way it has a little positive pressure on the BCG. like others have said, throw a quarter in the tube first as a spacer, then put the SCS back in. keep adding "spacers" till when you close the upper and lower, there is a little bit of contact between the BCG and the SCS. you should almost have to push the SCS back a little with your finger to close the system. that way you are insuring positive pressure on the BCG when its at a neutral state in the rifle.

if that still doesn't fix it, you might try a heavier spring. I have a few of these, and run some of the lightest springs without any issues (on lightweight BCGs). again, my guess is that there is a little slop between where the end of the BCG sits and the SCS stops causing this issue

 

[Saf3sh00t3r]

remember on the SCS setup, you need it more forward than a std spring and buffer would be. that way it has a little positive pressure on the BCG. like others have said, throw a quarter in the tube first as a spacer, then put the SCS back in. keep adding "spacers" till when you close the upper and lower, there is a little bit of contact between the BCG and the SCS. you should almost have to push the SCS back a little with your finger to close the system. that way you are insuring positive pressure on the BCG when its at a neutral state in the rifle.

if that still doesn't fix it, you might try a heavier spring. I have a few of these, and run some of the lightest springs without any issues (on lightweight BCGs). again, my guess is that there is a little slop between where the end of the BCG sits and the SCS stops causing this issue

Ben at JP told me not to use more than a couple of quarters. If that didn't help, heavier springs to preload would be better. I was also running suppressed to I had to use the 110% red and yellow spring. The springs are somewhere about $25.

 

[mpk1996]

Ben at JP told me not to use more than a couple of quarters. If that didn't help, heavier springs to preload would be better. I was also running suppressed to I had to use the 110% red and yellow spring. The springs are somewhere about $25.

yes, the quarters are spacers, not supposed to be for inadequate spring pressure. regardless of the spring, you need to insure that the SCS is setup with some preload. I usually order the 5 spring kit or the builder kit so I can tune the SCS. I just keep the extra springs cause who knows, I may change setups down the road, and then I already have the stuff I need.

 

[Saf3sh00t3r]

yes, the quarters are spacers, not supposed to be for inadequate spring pressure. regardless of the spring, you need to insure that the SCS is setup with some preload. I usually order the 5 spring kit or the builder kit so I can tune the SCS. I just keep the extra springs cause who knows, I may change setups down the road, and then I already have the stuff I need.

Been thinking about this, the spring is retained by the rod...so the spacers really don't add tension just move the rod forward creating te pushing function there additional preload? Right?

 

[mpk1996]

sometimes with out the spacer, the bcg will "float" as the distance from the back of the bcg to the end of the buffer tube can be longer than the captured length of the SCS. so, by adding the spacer, the SCS will always be in contact with the BCG. a way to think about it is running the SCS with a rifle length buffer. JP gives you the plastic spacer. but if you didn't run it, it would just flop around in the buffer. same thing here, but to a much less degree

 

[Hebrew Hooligan]

I just got mine in the mail yesterday and I had a little space between my BCG and the buffer. I tried putting that thin spacer they give you in the box (it looks like a C-clip) and that did almost nothing to fix the problem. It makes me wonder if that's really what it's for??? Either way I put 2 quarters in there and it's perfect now. I'm gonna have my friend print me a single spacer the size of the 2 quarters in ABS and see how that holds up.
Thanks for everyone who brought up the quarter trick my mind was drawing a blank on what to do to fix it.

 

[hlee]

I just got mine in the mail yesterday and I had a little space between my BCG and the buffer. I tried putting that thin spacer they give you in the box (it looks like a C-clip) and that did almost nothing to fix the problem. It makes me wonder if that's really what it's for??? Either way I put 2 quarters in there and it's perfect now. I'm gonna have my friend print me a single spacer the size of the 2 quarters in ABS and see how that holds up.
Thanks for everyone who brought up the quarter trick my mind was drawing a blank on what to do to fix it.

I’m pretty sure that c clip is used to retain the weights on the SCS.

 

[Hebrew Hooligan]

I’m pretty sure that c clip is used to retain the weights on the SCS.

Nice thanks man