JP VMOS or LMOS for 20" Suppressed 6.5 Creedmoor AR10?

[SMTGWKD]

As the title states, I'm interested in first-hand experience with either the VMOS, LMOS, or both as it relates to the following system:

DECIDED:
Barrel - Proof 20" with Camgas (Rifle +2")
Adjustable Gas Block - SLR Sentry 8 Titanium
Bolt - JP Enhanced High Pressure Bolt

UNDECIDED:
Buffer - EITHER Standard OR Heavy JP Silent Captured Spring depending on recommendations
Bolt Carrier - EITHER LMOS OR VMOS depending on recommendations

This is a lightweight build and the weight difference between the VMOS with Heavy SCS and LMOS with Standard SCS is about 7 ounces overall (which is very meaningful). However, I obviously want the best reliability, accuracy, and performance out of the platform. I plan to run this rifle suppressed 95% of the time.

I had decided on the LMOS with Standard SCS, but in a conversation with JP, they recommended the standard VMOS with a Heavy SCS to ensure the longest lock time of the bolt possible mentioning that even an adjustable gas block couldn't overcome that issue when suppressed due to increased effective dwell time (i.e. longer effective tube with longer duration of back pressure).

Questions:

1. Can the VMOS be stripped of some or all of the weights to become an LMOS carrier, in effect? Anyone tried this? If so, this may be the best of both worlds with the added versatility to tune.
2. From your experience (even with other calibers, but preferrably with 6.5 Creedmoor) how has your setup run with one or the other and which would you recommend if starting from scratch?
3. Which version of the Silent Captured Spring would you run given my parts list and your experience?

I anticipate ordering by this weekend and greatly appreciate any input!

 

[padom]

Hmmmmm.... I would go Rubber City Full Mass HP or JP LMOS with SCS Heavy. They will all work, but these combos will give you no case damage.

Are you having the proof spun up? If so go with a JP barrel.extension which is honed to prevent gauges out of the neck/shoulder. If you dont care about your brass than go with whatever

 

[SMTGWKD]

Interesting - never heard of Rubber City. Have you ever toyed with the VMOS? Do you know if one can simply remove weights on it? Says its modular on their website but I can't find any articles, videos, or otherwise that confirm (and I'm being lazy since they are closed to calls till tomorrow).

I'm purchasing a Proof Barrel that is ready to go - hadn't considered having them create one with the JP extension. Will the factory Proof extension eat my cases badly? As you likely know (you were really helpful while I was settling on a 6.5 load for my DTA) I reload so brass life is important, although not critical.

Hmmmmm.... I would go Rubber City Full Mass HP or JP LMOS with SCS Heavy. They will all work, but these combos will give you no case damage.

Are you having the proof spun up? If so go with a JP barrel.extension which is honed to prevent gauges out of the neck/shoulder. If you dont care about your brass than go with whatever

 

[padom]

Depends what barrel extension they use and if they hone it. If it's a straight out of the box BAT barrel extension they are sharp and gouge brass.

 

[jevan126]

First thing get the JP Silent Captured Spring, this is a must for all AR Rifles. I have them in all 3 of my JP Rifles and I just put one in my Nemo Arms Battle Light Rifle and what a difference.
Two I would go with the LMOS Bolt, I also have this in all 3 of my Rifles and it does a wonderful job with keeping control of Recoil.

 

[SMTGWKD]

Thanks - I believe Nemo runs adjustable gas blocks on their units. Do you run suppressed? If so, are you running the heavy Silent Captured Spring? Also, which caliber are you running?

First thing get the JP Silent Captured Spring, this is a must for all AR Rifles. I have them in all 3 of my JP Rifles and I just put one in my Nemo Arms Battle Light Rifle and what a difference.
Two I would go with the LMOS Bolt, I also have this in all 3 of my Rifles and it does a wonderful job with keeping control of Recoil.

 

[eklarsen]

I just did this, purchased the LMOS for a 6.5 CM, just recently replaced it for the VMOS and it is much better on brass and proper extraction. I would vote VMOS heavy and the SCS H2 for spring.

 

[JZimm9mm]

My experience with a suppressed JP LRP-07 in 308 is that the heavy SCS and heavy VMOS is easier on brass than the standard SCS and LMOS. I was getting a lot more expansion at the base of my cases with the lighter components. If you don't reload then just go with the lighter parts to compliment your light weight build.

 

[SMTGWKD]

Thanks for the input - after chatting with JP, Proof Research, and a couple of 3-gun friends, the answer was unanimous ... Heavy SCS with Standard VMOS. Since my barrel is a 20" camgas with adjustable gas block, each felt the very limited dwell time would allow me to run the standard VMOS with success. If I want to go heavier, I can always add a tungsten or two.

I do reload so brass condition is important - especially with a round like 6.5 Creedmoor. Thank you again for the first-person experience as it further validates the decision!

 

[eklarsen]

You will not regret it.

 

[jevan126]

I don't run suppressed on mine but it is a .223 Wylde and I am using standard ar-15 Captured Spring.

 

[chevytruck_83]

I just recently built a 6.5 creedmoor gas gun. After a ton of research I decided to go with jp precision’s 22” barrel with extra long gas tube. A shorter barrel with shorter gas tube can be problematic. Don’t believe me check out precision rifle blogs test where they compare high end bolt actions to high end gas guns. They had a LMT and POF has guns that wouldn’t function reliably. Only the jp precision did and the accuracy was dam close to the gap bolt action. I’m in no way tied to jp precision. I just know they shoot fantastic and my 6.5 creedmoor feeds functions and shoots awesome. No it’s not light but I’ll take function and accuracy over anything else. That’s the whole reason to go 6.5 creedmoor anyways.