Jp low mass carrier with sound suppressor

[BOOMSTICK]

Hello everyone this is my first post!  I am really into distance shooting.  I have been shooting for a while and have decided to change my tactics a little.  I have shot a 308 gas gun for about 6 years now and have had very good luck with them.  I have since shot out a 24" stainless heavy barrel and have decided to start over with my 308.  I recently purchased a 18" jp supermatch with enhanced bolt.  It has a midlength gas tube.  I am going to be running a YHM 7.62 phantom titanium suppressor.  The gun has been built with dpms upper and lower receivers.  I have always ran adjustable gas.  My question is I am recently aqquired a low mass bolt and captured spring from jp.  I have never had any reliability problems with the factory carrier or buffer/spring setup.  How will using the low mass carrier and captured spring work with the suppressor.  I know I will have to turn the gas pressure down.  I just have reservations taking weight off the carrier.  It seems like with the suppressor and the light carrier the bolt will be traveling at supersonic speeds even with the gas turned down.  I run my loads very hot.  What is everybodys thoughts on this.  Thanks

good to be here

[planeflyer21]

Welcome from AZ BOOMSTICK!

Someone will be along soon to answer your questions.

Jon

[unforgiven]

Welcome from Indiana brother BOOMSTICK.Maybe a heavy buffer from Clint one of our sponsors will help slow things down a bit. <dontknow>

[Robocop1051]

A heavy buffer would be counter productive to having a LMOS. Don't skimp on the adjustable gas block. A switch block won't work either. They are not calibrated for a LMOS. Stick to the parts that were designed to be used together. The JP LMOS is suppressor safe, and I'm sure any number of techs at JP would be willing to talk about it with you. You might have to fiddle with the adj GB a bit more due to the weight, but you should be fine.

[BOOMSTICK]

Thanks for the replies.  I understand what your saying about the heavy buffer.  I also have a jp captured buffer spring that is new.  I havent fired this rifle yet with the low mass carrier and the captured spring.  The only adjustable gas blocks I have used are jp's and I have had very good luck with them.  I just wanted to see how yall felt the carrier and spring would work with the suppressor.

[Rsquared]

Anytime you're running the suppressor, make sure that the carrier is lubed up well. These beast's like the carrier's pretty "wet" without the suppressors. I usually run a good light film of high temperature bearing grease on mine (plus a little on the lugs.....not too much though) when I'm planning to run suppressed. Different guys have different views on the grease on the lugs. I'm only speaking on what works well on mine (Armalite's). As with the gas.....even using hot loads, I find it always good to start it out tuned down low, and slowly work it up until the bolt holds open on the last round. I run adjustable blocks on just about all of mine and don't seem to have any issues. Now, with all of this said, I haven't tried using the LMOS carriers yet so I can't really have an honest opinion about them. I do know that others on the board use/or have used them, and are much more qualified to comment on them.

In short, trial and error is always a good solid form of testing to see how your rifle likes to run.

Ron

[98Z5V]

  I just have reservations taking weight off the carrier.  It seems like with the suppressor and the light carrier the bolt will be traveling at supersonic speeds even with the gas turned down.  I run my loads very hot.  What is everybodys thoughts on this.  Thanks

good to be here

Don't do it.  Based on your admissions, the LMOS ain't worth it.  Don't waste the coin.  Lightweight carrier, suppressor, hot loads, etc.  Blow that thing up and run it through the wall!!!  <dontknow>

My question is this - how do you run a hot load, on a suppressed rifle? Is the load subsonic, or not?

[Hooz]

The whole point of the LMOS systems revolves around having an adjustable gas block. If you adjust the gas correctly, the carrier won't have any more velocity suppressed than it will unsupressed... Because you're restricting the gas to the point that it only cycles the action, regardless of the setup.

If you're running unsuppressed, you adjust the gas so that the bolt just locks back on an empty magazine.

If you're running suppressed, you turn the gas down until the bolt just locks back on an empty magazine.

Either way, the end result is the same bolt velocity.

In a nutshell - You'll be fine shooting suppressed with a LMOS system as long as you tune the gas block correctly. That's exactly what they designed the system to do.

[planeflyer21]

So now that begs the question, why not only use the adjustable gas block and shuck the rest of the extras?

Jon

[Hooz]

Well, you could. But, the other benefit of using the LMOS system is that it reduces the reciprocating mass and reduces the "felt" recoil when shooting the rifle. The lower the reciprocating mass also keeps the gun flatter during recoil.

That's why 3-gun guys almost all run low mass systems (and adjustable gas blocks)... Less recoil and less muzzle rise lead to faster follow-up shots.

There was a great thread on this subject over at Sniper's Hide. One post there does a better job of explaining than I do.

There are two distinct recoil pulses in an AR-style rifle. One is the round going off (like a bolt gun has) the second is usually the buffer hitting the rear of the buffer tube. A lightweight carrier and/or buffer will do little to reduce the recoil by themselves. While the mass has been reduced' date=' the velocity has increased (which is why a more powerful spring is recommended).

If an adjustable gas block is used, the second recoil pulse can be eliminated completely. Instead of slamming to the rear of the buffer tube, the carrier and buffer simply go back far enough to strip a new round out of the magazine or lock back with the bolt catch. This eliminates the argument of decreased dwell time and torn up brass with a lightweight carrier and buffer.

With the second recoil pulse removed, the primary recoil pulse can be mitigated by a muzzle brake [i'](or suppressor). With the laws of physics being what they are though, the movement of nearly 1lb of steel back and forth internally will cause the rifle to move, hence the desirability of the lightened components.

[planeflyer21]

<thumbsup>

Jon

[BOOMSTICK]

Thanks for all of the input.  My loads are not subsonic.  I already have the low mass carrier and captured spring.  I picked them up cheap and thought I would try them.  If they dont work then no harm done.  I will just sell them.  What about bolt bounce.  I have never experienced it that I know of.  With the increased forward speed of the bolt and not having the extra weight on the carrier to you run an increased risk of the bolt bouncing out of battery? 

[edgecrusher]

I believe what Hooz said holds true here, use your adjustable gas block to lower the gas rate, and it'll be a non issue. It sounds like a lot of trial and error but worth while

[Hooz]

People who run lightweight carriers and buffers in their ARs typically run extra power action springs. Since there is less mass slamming the bolt home, the spring helps, and it also mitigates bolt bounce. The JP captured spring is designed to run with their carrier, so you'll be fine.

But like I said earlier, you adjust the gas to your operating system. There is no "over gassing" or accelerated carrier velocity because you tune it to your setup... Stuff only moves as fast as it needs to.

I have low mass systems in two ARs, and I'm putting one in my LR308 build too. I like them a lot.

[CMAN]

Welcome from CO BROOMSTICK!