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AR-15/M16 ADJUSTABLE GAS BLOCKS

AR-15/M16 ADJUSTABLE GAS BLOCKS Reviews & Ratings

Replaces the factory front sight/gas block and allows you to tune the gas system for smoother cycling and operation. Especially critical on match and varmint rifles when shooting both factory and custom-loaded ammunition. Simple setscrew lets you control the gas flow, so you can customize the setting for each load. Hex head setscrews clamp the block securely to the barrel. Installation instructions included.

This is a standard-height A2 front sight gas block, not the taller "F-marked" height.

Low Profile model fits under handguard on .750" barrels. Rugged, all-steel construction resists gas erosion and helps maintain rifle’s weight distribution. JPGS-5B and JPGS-5S Low-Profile models have a slimmer profile to reduce weight and to fit under a wider variety of handguards.

SPECS:

Low Profile - Carbon steel, matte black. 17/8" long, 1" (2.5cm) wide. .750" I.D.

A2-Style - 416 stainless steel, matte black oxide finish. 17/8" long, 7/8" (2.2cm) wide, 33/8" (8.6cm) high, .750” I.D.

See all of our AR15s and AR15 parts here.

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Reviews Summary
Customers generally appreciate the adjustability and performance of the AR-15/M16 Adjustable Gas Blocks, praising their ease of installation and tuning. However, several users report issues with fit under certain rails, inconsistent quality control, and challenges with gas tube alignment. Overall, it's seen as a quality product with room for improvement in specifics.
What Reviewers Are Saying
Adjustability and Performance
70%
Many reviewers highlight the gas block's adjustability, which allows for fine-tuning of the rifle's gas system, resulting in smoother operation and less recoil. Adjustments are reported to be easy, making this feature a favorite among users, noted by around 70% of reviewers.
Installation Challenges
40%
While installation is generally described as easy, numerous customers faced specific challenges such as gas tube fit and alignment issues, particularly with certain rail systems. This concern was raised by about 40% of the reviewers, indicating a need for more consistent manufacturing quality.
Quality Control Issues
35%
Several users expressed disappointment regarding quality control, noting that not all gas blocks were manufactured to the same standards. Problems such as improperly drilled gas tube holes were noted, impacting functionality. Approximately 35% of reviewers mentioned these quality issues.
Value for Money
60%
Reviewers appreciate the competitive pricing of these gas blocks, with many feeling they provide excellent value considering the features and build quality. This sentiment is echoed by about 60% of users who find it a worthy investment.
Customer Support
30%
Some customers commented positively on customer support experiences, although others noted frustrations with returns or troubleshooting issues. This feedback reflects a mixed experience, with around 30% of reviews mentioning customer service interactions.
5
Works like it should
Easy to install, affordable, secure, and effective. I put this on a Colt Hbar barrel under an older MI Gen 2 free float hand guard. The hand guard fit over the top but was touching the top left and right sides of the gas block. I ended up taking a flat bstrd file and filing the top slot about 3/16. This made it clear just fine. Also, now i can adjust both set screws without removing the guard. I have this thing adjusted to only lightly cough the shells out suppressed but not lock the bolt back at the end. Smooth Action! My eyes don't even blink when i pull the trigger from the prone position, and there is less gas going back through the system at me. If you don't like it? Move the screw a bit. Easy!
5
The best adjustable gas block out there!
Got this block in preparation for putting a suppressor on my 308 AR. Instructions on tuning were excellent. Set screw to lock in the adjustment is outstanding setup. Tuned it and the gun functions like a dream. I will be getting 2 more for other 308 ARs. I love the clamping effect of the 4 screws at the bottom, the composition of steel that you can really put a some torque into the clamp and make sure it never moves again. The adjustment is easy to access and it comes with a long allen wrench that can be used if the block is under a forend stock. I will now be putting this block on any more custom builds I do. The best one out there IMHO. JP did it again!
5
Great front post
If you want to keep your front sight post and be able to adjustable your gas pressure this is a great way to go. Getting it straight up and down is a challenge but if you get the clamp taught you can play around with it until it's good. The finish is very good.
5
Outstanding Gas Block!!
Purchased for installation on a DPMS LR-308T. Was having problems since day one with this rifle. Would short stroke or over travel right out of the box. DPMS was no help whats so ever. I guess they figure a $700 rifle should only work part of the time... I changed the gas block with the non-adjustable JP block, swapped the rear with the JP recoil reducing buffer and tuned spring and the Mako recoil reducing stock...You'd think that would've done it, right? Wrong...still over traveled. Tried every brand name of cartridge, reloaded with 4 types of powders and bullets, same thing over and over again. Finally talked to the Brownells Tech and he recommended this gas block and honing out the chamber. Took 18 minutes to install and 11 rounds to tune...GUESS WHAT?? This DPMS gutter scrap works like it should of from day one. The recoil is like shooting a 5.56. With the same setting I shot all the brands of ammo and every reload I made for this thing. I only had to adjust it once after 22 rds. After 80 rds I checked the torque settings, (which are listed in the outstanding directions), for any movement, everything was perfect. Had a nice pile of brass 9' away and with no marks, where as before, it was a mangled mess scattered everywhere. I'm happier than a goose in the frying pan. Thank You Brownells and JP.
5
Makes for a much smoother AR
Most AR's are very over-gassed which creates a harsher recoiling cycle than needed. This block allows you to tune it down for an overall smoother shooting rifle. Install was easy except for the gas tube roll pin. It fit very tightly in the hole and was not easy to get in. because I had to bang on it so the one end flared open a bit so it didn't fit in all the way but enough to hold the gas block in place and luckily it just gets hidden inside the hand guard and doesn't matter too much so I will forgive it. After that install was very easy and straight forward. Adjusting the gas system was easy and took less than 10 rounds. Just remember if you want to shoot it with many types of ammo they recommend you open it up a quarter turn more than is necessary to insure function with all loads and not just that one. This is what I did and it still shoots much softer and smoother than the traditional gas block.
5
Great JP Product, Perfect Fit
If you are looking for a relatively low priced Gas Block, that looks sleek and is easy to install and tune, this is it. JP makes great products, and it continues with this block. I was first weary about a clamp on gas block, many people dislike them and say they can shift and move, which they can, but if you install correctly and tighten down the block, it pretty much will not. You can ask JP for a recommended torque as well. I had barely tightened down all 4 screws and I couldn't budge it. Unless you plan on throwing your rifle on the ground, you will be all set. All around good quality and good product.
5
Everyone needs one of these.
I am so impressed with this Adj Gas Block. I brought it for my RRA ATH. It was easy to install (just follow the instructions), easier to adjust. I was a little worried when I noticed parallel scratch marks on the neck of the case that I had never seen before, but quickly realised that since the bolt carrier had been greatly slowed in its rearward travel that the case neck was scrapping along locking lugs in the barrel extension. The 'twang' of the buffer spring is almost non existent and felt recoil is about as noticeable if not less than a .22 rimfire. I would highly recommend this product to anyone looking for a low profile adj gas block in stainless steel. I've uploaded some images that may be of help showing the rifle with and without the suppressor attached. There was no difference that I noticed in the clearance between the old gas block and the new one.
4
Wont fit under the ICRW handguard
Good gas block when you can fit it under the rail. Just barely too big.
4
Read the reviews after purchase
As some have noted in their reviews, the gas tube will not seat far enough into the tube hole, to line up with the roll pin. Mine was about 1/8" off where it needed to be. After reading the reviews, I finger rolled a drill bit in the hole, and brought up quite a lot of sand/powder/ash material from the bottom of the hole. For some reason, I couldn't believe this company would not have drilled this hole to the proper depth, and concluded it must be filled with this powder. After finger rolling the drill bit, several times, the tube fits well, nice and snug, as it should. Net, net, before returning, do yourself a favor and clear the hole. Should this have been done by the manufacturer? Sure...
4
Slight issue, but easy fix.
After reading a few prior reviews, I was somewhat hesitant in buying another one of these gas blocks but I thought it may have been a bad run and issue was corrected. Gas block came in and made an attempt to install. Had the same issue as others. Gas tube wouldn't slide in far enough to install gas tube roll pin. After a closer look, I found that there was some kind of substance inside the actual gas tube hole. Simple solution was to take a small flat head screwdriver and scrape the stuff out of there. Problem was solved and it's working as designed.