Jump to content
308AR.com Community
  • Visit Aero Precision
  • Visit Brownells
  • Visit EuroOptic
  • Visit Site
  • Visit Beachin Tactical
  • Visit Rainier Arms
  • Visit Ballistic Advantage
  • Visit Palmetto State Armory
  • Visit Cabelas
  • Visit Sportsmans Guide

[Review] JP Rifles Low Profile Adjustable Gas Block


Guest LLArms

Recommended Posts

Finally this past weekend had a chance to put this thing through the paces.  We have a right hand side charging handle modification on one of our LR-308 platforms and wanted to simply test the ease and ability to have a gun that can move between a single shot and semi-auto mode.  This would also allow us to make sure brass was ejecting to the proper region, or fire over-sized loads that will not fit in a magazine.

The only thing I did not like was the set screw/bit you turn to adjust the amount of gas.  I replaced this was a longer hex screw (same threading/size).  My plan is to eventually have a "knob" or "handle" machined to replace this so it can be adjusted by hand with no tools.  Other than this one preference, (which to some is subjective) I can find nothing negative to report.  Well worth the $79.95 + Shipping to purchase.

- Turning the set screw all the way in effectively turned our LR-308 into a single shot weapon, which increased accuracy slightly due to no moving parts upon firing the cartridge.

- Once we found the "sweet spot" with the set screw opened up, we had our brass piling up in the same general area in the 3 to 4 o' clock position and in 300 rounds we cycled through had zero FTE or FTF

JP Rifles fails to let me down, again. We also use their muzzle brakes (.950 Large Profile) and they too are top notch products. Very loud, but very effective.

We hope to get our hands on one of their "Silent Captured Springs" soon as it has received stellar reviews.  <thumbsup>

2173.jpg

JP Adjustable Gas System for AR type rifles.

Low profile, rail-free design allows installation under hand guards.

Material: 6061 T6 Aluminum

Finish: Black Hardcoat Anodized

Weight: 2.7 oz

Length: 1.880”

Height: 1.395"(overall), .770"(over bore)

Width: 1.44"

Minimum recommended tube ID 1.750” (allows mim .050” clearance on all sides)

Attachment: 6-32x1/2" socket head screws, T15 Torx drive (Torx key included)

(includes 5/64x1/2 roll pin for gas tube installation)

Adjustment: 6-32x3/8" stainless set screw, 1/16 hex drive (hex key included)

Link to comment
Share on other sites

Nice review! I like that design of the GB. Especially for the weld on muzzle device states.

Adjustable GB's might be the next answer for Californians if the "Bullet-Button Ban" ever gets enough momentum. If so, that tool idea could be a $million idea.

Adjusting a GB to close off the gas (or eliminating a GB completely) essentially turns the rifle into a single shot firearm. No different than a bolt rifle. Instead of the normal, charge-BANG-BANG-BANG, you get charge-BANG-charge-BANG-charge-BANG.

I had thought about a second modification that engaged the bolt catch after every shot, which would also require releasing the bolt prior to each shot. Again making the firearm into a single shot. This would be most beneficial with something like the Mega Arms or AXTS ambidextrous lower receivers, each with a bolt release within reach of the trigger finger. Similar to the single shot, but half the operation would already be done for you. Instead of the above you'd go, charge-release-BANG-release-BANG-release-BANG

Link to comment
Share on other sites

Nice review! I like that design of the GB. Especially for the weld on muzzle device states.

Adjustable GB's might be the next answer for Californians if the "Bullet-Button Ban" ever gets enough momentum. If so, that tool idea could be a $million idea.

Adjusting a GB to close off the gas (or eliminating a GB completely) essentially turns the rifle into a single shot firearm. No different than a bolt rifle. Instead of the normal, charge-BANG-BANG-BANG, you get charge-BANG-charge-BANG-charge-BANG.

I had thought about a second modification that engaged the bolt catch after every shot, which would also require releasing the bolt prior to each shot. Again making the firearm into a single shot. This would be most beneficial with something like the Mega Arms or AXTS ambidextrous lower receivers, each with a bolt release within reach of the trigger finger. Similar to the single shot, but half the operation would already be done for you. Instead of the above you'd go, charge-release-BANG-release-BANG-release-BANG

Wouldn't the device that engages the bolt catch negate any gain in accuracy since you are now adding back in a moving BCG? Sounds like all that device does is stop the loading of another round.

With this GB the BCG never moves after the shot, you have to rack it to load a new round.

Link to comment
Share on other sites

Wouldn't the device that engages the bolt catch negate any gain in accuracy since you are now adding back in a moving BCG? Sounds like all that device does is stop the loading of another round.

It'd be no less accurate than shooting the last round in the magazine of a regular rifle. The bolt would still hang open in that case.... Like I said, it was just an idea. I like the idea of limiting gas as well, but then you run into over gassing issues.

Link to comment
Share on other sites

  • 2 weeks later...

Finally this past weekend had a chance to put this thing through the paces.  We have a right hand side charging handle modification on one of our LR-308 platforms and wanted to simply test the ease and ability to have a gun that can move between a single shot and semi-auto mode.  This would also allow us to make sure brass was ejecting to the proper region, or fire over-sized loads that will not fit in a magazine.

The only thing I did not like was the set screw/bit you turn to adjust the amount of gas.  I replaced this was a longer hex screw (same threading/size).  My plan is to eventually have a "knob" or "handle" machined to replace this so it can be adjusted by hand with no tools.   Other than this one preference, (which to some is subjective) I can find nothing negative to report.  Well worth the $79.95 + Shipping to purchase.

- Turning the set screw all the way in effectively turned our LR-308 into a single shot weapon, which increased accuracy slightly due to no moving parts upon firing the cartridge.

- Once we found the "sweet spot" with the set screw opened up, we had our brass piling up in the same general area in the 3 to 4 o' clock position and in 300 rounds we cycled through had zero FTE or FTF

JP Rifles fails to let me down, again. We also use their muzzle brakes (.950 Large Profile) and they too are top notch products. Very loud, but very effective.

We hope to get our hands on one of their "Silent Captured Springs" soon as it has received stellar reviews.  <thumbsup>

Heat transfer to the knob , may make it un-adj., if firing long strings with out gloves . Also the larger the knob , vibration may loosen even the best loc tight , a locking or cinch nut may be needed .

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...