AR Buffer Spacer

Diver43

To make a long story short, I had a bunch of parts and put together a AR lower with A-2 stock.
Not having one and against @Zee s opinion, I picked up a inexpensive .300 blackout, side charging upper.  Took the gun to Fishhead's ranch and first shot rang the gong.  However a second round was not fed.
Tried a few other magazines same outcome. I/we thought the range ammo 1850 fps at the muzzle  was not powerful enough to send the bolt all the way to the rear, and a piece of tap on the gun showed that to be correct.
Doing some research this seems to be common problem with .300BO when the upper is a carbine length gas system and using a A-2 or full length stock/buffer.
Easy fix should be put the upper on a Carbine stock and call it good, but then I have this A-2 stock that I like.  Another fix would be to use a carbine spring and buffer with a spacer.  I thought that I knew a little about ARs, but the spacer is new to me.  Anyone use one?  Is it worth the effort?  What says you all that know more than I

Zee

I do like the A2 stock. And for the record, I have no problem with you gender transitioning by the purchase of a .300 BO. It’s the times. It’s popular. Transitioning, I mean. 😁

I’ve no experience with a spacer. But, there are also lighter buffer springs and buffers that might be an option. Just thinking. 

shotgunshooter3

I would look for a lighter spring before trying to mess with adapting buffers etc. Sprinco seems to be well regarded. 

Bigslug

Do you have a shortage of local friends with M4 pattern carbines?  Seems like you should try a game of musical lowers to confirm a working combination of parts - - including your relatively untested upper - - before playing accessories roulette with your VISA card.

Diver43

Thanks for the input 
Lighter buffer (3 oz) seems to be what is needed.
First I will put it on a carbine lower and see if that works.  

Wambli Ska

Diver43 said:

Thanks for the input 
Lighter buffer (3 oz) seems to be what is needed.
First I will put it on a carbine lower and see if that works.  

Good plan.  I’m not a big fan of “spacers” of any kind.  Always seems to me like a bandaid.  Buffers and springs can be had in all sorts of weights to fine tune.

Diver43

Wambli Ska said:

Diver43 said:

Thanks for the input 
Lighter buffer (3 oz) seems to be what is needed.
First I will put it on a carbine lower and see if that works.  

Good plan.  I’m not a big fan of “spacers” of any kind.  Always seems to me like a bandaid.  Buffers and springs can be had in all sorts of weights to fine tune.

I didn't know they made adjustable buffers.  If it works with a carbine lower, forget the spacer,  will pick up a adjustable buffer and keep my preferred A2 stock.

Wambli Ska

Diver43 said:

Wambli Ska said:

Diver43 said:

Thanks for the input 
Lighter buffer (3 oz) seems to be what is needed.
First I will put it on a carbine lower and see if that works.  

Good plan.  I’m not a big fan of “spacers” of any kind.  Always seems to me like a bandaid.  Buffers and springs can be had in all sorts of weights to fine tune.

I didn't know they made adjustable buffers.  If it works with a carbine lower, forget the spacer,  will pick up an adjustable buffer and keep my preferred A2 stock.

Don't now enough about ARs to know about "adjustable" buffers, but the amount of buffers (weight and sizes) and springs out there is overwhelming.  You can fine tune almost any combination.

Diver43

Wambli Ska said:

Diver43 said:

Wambli Ska said:

Diver43 said:

Thanks for the input 
Lighter buffer (3 oz) seems to be what is needed.
First I will put it on a carbine lower and see if that works.  

Good plan.  I’m not a big fan of “spacers” of any kind.  Always seems to me like a bandaid.  Buffers and springs can be had in all sorts of weights to fine tune.

I didn't know they made adjustable buffers.  If it works with a carbine lower, forget the spacer,  will pick up an adjustable buffer and keep my preferred A2 stock.

Don't now enough about ARs to know about "adjustable" buffers, but the amount of buffers (weight and sizes) and springs out there is overwhelming.  You can fine tune almost any combination.

The buffer has weights that can be added or removed.
Won't know for sure until I get to the range, but if I'm right, I need a rifle sized buffer that weighs only 3 oz

Wambli Ska

Diver43 said:

Wambli Ska said:

Diver43 said:

Wambli Ska said:

Diver43 said:

Thanks for the input 
Lighter buffer (3 oz) seems to be what is needed.
First I will put it on a carbine lower and see if that works.  

Good plan.  I’m not a big fan of “spacers” of any kind.  Always seems to me like a bandaid.  Buffers and springs can be had in all sorts of weights to fine tune.

I didn't know they made adjustable buffers.  If it works with a carbine lower, forget the spacer,  will pick up an adjustable buffer and keep my preferred A2 stock.

Don't now enough about ARs to know about "adjustable" buffers, but the amount of buffers (weight and sizes) and springs out there is overwhelming.  You can fine tune almost any combination.

The buffer has weights that can be added or removed.
Won't know for sure until I get to the range, but if I'm right, I need a rifle sized buffer that weighs only 3 oz

Oooooooooh adjustable for weight, I was thinking length.  That should work.

Diver43

Bigslug said:

Do you have a shortage of local friends with M4 pattern carbines?  Seems like you should try a game of musical lowers to confirm a working combination of parts - - including your relatively untested upper - - before playing accessories roulette with your VISA card.

Have a few, will try them first of course. Unfortunately I cant test the gun in my backyard 😥
And my rat / gun money is on a Mastercard 

GrapeApe

I'm curious where you got your data about carbine length gas systems? I know they're claimed to be less reliable with subsonics, but have always been told, "pistol length for subs and carbine length for supers"

I know that my 2 16" carbine length uppers were both so "over gassed" I had to put adjustable gas blocks on them to slow down the recoil pulse. One resides on an A2 lower and the other on a carbine stocked one

edited to add: the "bolt lock back" test is a good way to check function and is how my adjustable blocks instruct how to set them up.

One round in a mag, fire and make changes based on if the bolt is locked back, or not. You can probably adapt that test for your changes of springs, buffers etc.

Diver43

GrapeApe said:

I'm curious where you got your data about carbine length gas systems? I know they're claimed to be less reliable with subsonics, but have always been told, "pistol length for subs and carbine length for supers"

I know that my 2 16" carbine length uppers were both so "over gassed" I had to put adjustable gas blocks on them to slow down the recoil pulse. One resides on an A2 lower and the other on a carbine stocked one

edited to add: the "bolt lock back" test is a good way to check function and is how my adjustable blocks instruct how to set them up.

One round in a mag, fire and make changes based on if the bolt is locked back, or not. You can probably adapt that test for your changes of springs, buffers etc.

While my first move will be to try 3 other lowers that are not identical to the one in question.  5.56 uppers have no problem with the A2s stock rifle length/weight buffer, it seems .300 BOs built with a carbine length gas system do.  Judging by comments online several folks have had the same issue with a A2 stock