Category Archives: JP Enterprises

New 9mm Silent Captured Spring by JP Enterprises


JP Enterprises just released their new 9mm Silent Captured Spring which is a complete buffer and spring system for 9mm AR-15 carbines and pistols.  The concept of the JP Silent Captured Spring is to eliminate the spring noise in the buffer tube than many find irritating and make the smoothest possible feel to the action.  The standard AR15 variant of the Silent Captured Spring has been extremely popular and has consistently been a top product with our customers.  But the 9mm model is brand new for July 2014.  We have had them on order with JP for months and finally got the first batch of them in.  They have 4 weights instead of 3 on the .223 model and the weights are tungsten instead of steel to provide more weight for the 9mm blowback operation.  One thing to note is that all JP Silent Captured Springs, this one included, require the guide rod to be able to extend into the rear portion of the bolt/bolt carrier as the action cycles.  On most 9mm bolts there is a steel weight secured into the rear of the bolt with a roll pin to add weight.  In order to use the JP Silent Captured Spring system, this weight must be removed.  The buffer system adds enough mass to for it to still function properly with the weight removed from the bolt.  This is a simple operation just requiring a punch to drive out the roll pin and slide the weight out the rear of the bolt.  So for those looking for a smooth buffer system for their 9mm AR15 carbines, pistols or SBRs, here’s a great new option for you.  For further details and to buy see the 9mm Silent Captured Spring at

Why Would I Want an Adjustable Gas Block?

Adjustable gas blocks come in a number of forms.  Some have 3 pre-set positions that the operator can select like “normal”, “adverse” for when your gun is really dirty and you don’t have time to clean it, and “off” for when you want to manually cycle the action.  Some have settings for “suppressed” for when using a sound suppressor.  These are most common on military rifles and one of the earliest was the Belgian FN-FAL.  It’s gas block had a nut that could be unscrewed one click at a time which gradually exposed a gas port which would vent excess gas pressure.  This threaded nut concept is useful because the operator could set it exactly where he wants it for his gun and his ammo instead of just having a “normal” or “adverse” setting.  This ensures the gun is set to where it will run reliably without running excessively hard causing more recoil and wear on parts than necessary.

FAL gas regulator


This concept has made it into the aftermarket parts industry as well for guns like the M1 Garand and AR-15 where adjustable gas plugs or gas blocks can be installed by the operator or a gunsmith.  I’ll focus on the AR-15 adjustable gas blocks since they have become quite popular for those building custom guns or upgrading their current rifle.  A few years ago, when adjustable gas blocks were relatively new on AR-15s, they simply consisted of a gas block with a screw in the side that would gradually cut off the gas flow from the barrel to the gas tube as you screwed it in.  This is the simplest type to manufacture and quite a few companies make them now.  Some of the most popular examples of these are made by JP Enterprises which have been around for years.  PRI has also made one for a while and Wilson Combat and several others have recently come out with their own designs. These work well, but the screw isn’t secured in any way, so it could technically drift since it’s not locked in place.  In practice, carbon builds up in the threads and normally keeps the screw setting stable.  This style is still widely used and liked today, especially for competition shooters.


But many shooters want things that are locked down and can’t come loose during a competition or a self defense situation no matter what.  So this led to adjustable gas blocks with lockable settings.  Lockable settings can consist of a second screw that is tightened into the side of the adjustment screw to lock it into position once you got the setting where you want it.  This is a simple approach that works and is used on some high quality gas blocks like those from Seekins Precision.  The Seekins Precision Adjustable Gas Block uses a brass locking screw to secure the set screw.  The most recent development are those with spring loaded detents which click into position every quarter turn as you adjust the set screw.  Popular examples of these are made by Syrac Ordinance and SLR Rifleworks.  The nice thing about this is that all you have to do is turn the set screw with an Allen wrench and it locks in place automatically as you go, so you don’t need to tighten a second screw and it stays very secure on the setting you want and it’s easier lock into position while under a handguard.  Additionally, with audible click settings, you can keep tract of settings and adjust it by a known number of clicks for a certain type of ammo for example.



So what can you expect to get from using and adjustable gas block on your AR-15 or AR-10 type rifle?  Many guns come over-gassed from the factory and run the bolt carrier group harder than it needs to, so it can be tuned down a bit to feel softer recoiling while still functioning properly.  You also have the option of trying a different buffer system and optimizing the gas flow to work with that buffer.  One of the most effective ways to use an adjustable gas block is to pair it with a lightweight bolt carrier and then tune down the gas to get the speed and reliability right.  This makes for less reciprocating mass for less movement of the gun as it cycles and quicker sight picture recovery for the next shot.  This concept was popularized by JP Enterprises as the Low Mass Operating System or LMOS and now several other manufacturers are making light weight bolt carriers as well.  A fringe benefit of tuning down the gas is that it may run a bit cleaner with less gas going through the bolt carrier.


Not all ARs can benefit from and Adjustable Gas Block since some don’t have too much gas coming out of the gas port and you wouldn’t want to tune it down further.  But for guns running very hard, or for those who want to use a light weight bolt carrier, it can be very useful.  One thing to remember is that you can’t increase gas pressure with an adjustable gas block.  The full pressure is determined by the gas port location and size in the barrel.  An Adjustable Gas Block can only tune down gas pressure.  But they do have a useful place in firearms design and are something you might want to consider if building or customizing an AR type rifle.

Customer Review: Kynshot AR-15 Carbine Buffer with JP Buffer Spring

Jason, of Indiana, emailed us a GREAT review of the Kynshot AR-15 Carbine Buffer and the JP Buffer Spring for the AR-15 Carbine ! Here’s what he had to say:

“I received the Kynshot and JP spring Friday before I left for work.  I got them both installed, but I didn’t have time to shoot it until Saturday.

Saturday, I went out with my 9 yo son for some shooting.  We were sighting in some new ammo I just received that morning, Federal 5.56 XM-855. I am assuming that ammo packs a little more punch than .223.  It was very comfortable for both of us to shoot.  The recoil is still there, bu it is spread out over time, instead of a quick shot.  I’m really happy with the upgrade.

It does shoot smoothly, and also muzzle rise is reduced.  My 9 yo noticed and could explain the difference he felt in shooting.  He is as unbiased as you can get.  All he knows is what happens when he pulls the trigger, and he likes it.  He said the same that I thought.  It doesn’t kick as hard, and the red dot doesn’t go up near as much.  I should have him write a review!

Thanks again for all your help.”

Thank you, Jason, for shopping at!

If you found this review helpful, click here, scroll down till you see the review and where it says “Was this review helpful?” click “Yes”.  Thanks!

#kynshotbuffer #jprifles #nokickwebstore #ar15

Customer Review: JP Enterprises AR-15 Silent Captured Spring

Adam from Ann Arbor, Michigan gave the JP AR-15 Silent Captured Spring a 5 Star Review!  Listen to what he had to say:

“silent capture: I have owned as well as been issued AR’s for 30 years. This is an incredible upgrade time will tell if the design will hold up but what a difference in how smooth the weapon operates now.”

Thanks Adam for shopping at!

And if you found this review helpful, please go here, scroll down to the review and where it asks ‘Was this review helpful to you?’ please click ‘Yes’. Thank you!