Buffer weights and why they are important.



You absolutely can.
Keep in mind if this is your defense rifle I would rather it be slightly over gassed than under gassed IMO. I would take that over being in a situation and having the rifle not being able to properly cycle.
Just add one tungsten weight at a time.
Load 1 single round into your magazine and shoot your target. ( keep adding 1 weight and 1 tungsten weight) As soon as the bolt fails to lock back after your single round is fired just remove the last tungsten weight that you added.
You have a lot of options with a rifle buffer. Room for five weight!


Good advice, thanks.


Interesting site! I’m glad that someone is building heavy buffers. I use a lot of 303 stainless steel myself.

Mostly for brakes or tools in my case.


I haven’t used one of those yet, but a guy I go shooting with has had one break on him during shooting.
It may have been a one in a million chance, but that’s not a chance I personally would take.
You know me jf89 I’m a little old school.


I have actually been wondering about the durability of them. They do not seem to be built as sturdy as standard buffer set ups or A5 set ups. Cool concept though.


It is. I look at it like this. The company that makes them does one thing. Make one heck of a competition rifle, not a defense rifle. Just my two cents.


I looked into the JP scs for this AR10, but just couldn’t spend the coin on something I wasn’t sure would help. It also is adding more parts to a simple system, that was another factor in not going with it. Plus side is once tuned they are quieter.


I run one in my go to rifle. It shoots like buttered glass. No problems with it so far, but it is slightly obnoxious to remove from the buffer tube.

@switchpod, you ever peaked at Kyntec’s hydraulic buffers? KynSHOT Marksmen Buffer


Nope, but I just clicked on the link you have supplied. Thank you for showing me this. I’m interested in what it weighs to be honest.


Back to your AR9 question! I had 5 minutes to do this so for give the pictures.

Here is a stock AR-15 carbine buffer spring

Now keep in mind that this is a crude test. Here is the set up.
I am going to add weight until all the coils are compressed and touching.

It took 17.5 lbs to get us to full comprehension.

Now for full disclosure ( I don’t have the specs/ weight of a 9mm “ar9” bolt carrier assembly) I will be using an AR15 bolt Carrier weight instead.

The weight is ~11.7oz plus a buffer let’s say an H buffer at 3.8oz the total is 15.5oz just .5oz shy of a full 1lb.

Now let’s look the weight of a slide on a stock Glock 17.

This come up at 1lb 1.125oz of weight.
Let’s look at the recoil spring.

This stock 9mm Glock model17 recoil spring took 16 lbs to compress!

So what can we learn from this very crude information? We learned that even though the 9mm cartridge is smaller that a .223/556 cartridge there still is a lot of power in the 9mm. The recoil springs between the Glock and the ar-15 is 1.5lbs, and the slide weights 1.625oz heavier than the ar-15 bolt carrier and buffer weight!

Take what info you want from this very non scientific test method, but I feel that what we found is consistent with what @Greenwell_Armory noticed about the wear he saw on his rifle with a relatively low round count!
Keep in mind that there are many more factors to consider with recoil and the many differences in a pistol design and a ar-15 design, but like I always say be safe and have fun!


Yep going to definitely get a heavier buffer setup for the final build.


first I’d look at the chamber could have carbon build up or scratches etc. that stick the case.
The design purpose of the buffer is to prevent bolt bounce on full auto. Too heavy a buffer will result in stoppages. Buffer weights are designed for operation in all temperatures/conditions.
That you can play with the weight on semi autos at the range is fine but when you depend on your firearm to go bang every time stick with the proper buffer.


I am having a little experiment with all of this that you might find interesting. It may take awhile due to time constraints, but I will make sure I type @jtallen83 when I post it!


Link to building a heavy buffer!


Put in my spikes 8oz Heavy 9mm buffer and what a difference!


So a revisit from last fall. I’ll spare you all a lot of pictures. I got the tungsten weights and eventually added all 3 to this rifle length buffer. Did function checks after each addition and liked how the rifle worked, this was at the house. So today off to the bench rests to check zero and see how well I could stay on target. I also made the rifle spend the night in the truck so it would be a cold start to the session. Low was at 24f.

100yd zero for this setup


So the shot groups after checking zero same distance, under 10 seconds per group.


Those groupings are all different factory ammo. Shoot n c is perfecta 147gr 308, upper middle is hornady 155gr amax 308, upper lower is federal 150gr sp power shok 308.


Nice group! I’m glad that the rifle is running smooth for you Brother!