Buffer tube weight and spring for 300 BLK

JT300

Smooth Brain in Alabama only local preferred
Jun 2, 2022
203
94
Calera AL
Buffer tube weight and spring for 300 BLK ill be shootin subs and supers any advice would be greatly appreciated
 

Dfalt

Established Member
Mar 13, 2021
786
929
Troy, AL
Basically the weights in your buffer provide resistance to the force from the recoil pushing your bolt back. Heavier weights are better for shorter barrels and/or suppressor use since they counteract the extra pressure those setups go through (and give you less felt recoil) but can cause short-stroking with lighter loaded rounds. The buffer weights are usually made of steel but for heavier buffers some or all of the weights are made from tungsten. The H designation tells you how many of the weights are tungsten as opposed to steel, so an H3 has 3 tungsten weights where and H0 would have none and all the weights would be steel. H3 is usually a good all-around to get the benefits of a heavier weight buffer without running into too much short-stroking, but if you do you can always bump down a weight or two.

What barrel length are you using, and are you going to be using a suppressor any?
 

JT300

Smooth Brain in Alabama only local preferred
Jun 2, 2022
203
94
Calera AL
Basically the weights in your buffer provide resistance to the force from the recoil pushing your bolt back. Heavier weights are better for shorter barrels and/or suppressor use since they counteract the extra pressure those setups go through (and give you less felt recoil) but can cause short-stroking with lighter loaded rounds. The buffer weights are usually made of steel but for heavier buffers some or all of the weights are made from tungsten. The H designation tells you how many of the weights are tungsten as opposed to steel, so an H3 has 3 tungsten weights where and H0 would have none and all the weights would be steel. H3 is usually a good all-around to get the benefits of a heavier weight buffer without running into too much short-stroking, but if you do you can always bump down a weight or two.

What barrel length are you using, and are you going to be using a suppressor any?
9 or 10in 1:7 twist 300 blackout and yes i will be using a suppressor but not sure which one also ill have a 11.5 556 upper that ill switch to from time to time i will most likely have to get a different buffer for that upper i imagine. Thanks and brands or does that even matter on buffers
 

Dfalt

Established Member
Mar 13, 2021
786
929
Troy, AL
I'd recommend VLTOR for the buffer and Sprinco for the spring. It's optional but the A5 buffer tube VLTOR makes (BCM makes one as well) is a nice upgrade as you can use a rifle length spring in a tube that's only slightly longer than a standard carbine tube.
 

JT300

Smooth Brain in Alabama only local preferred
Jun 2, 2022
203
94
Calera AL
I'd recommend VLTOR for the buffer and Sprinco for the spring. It's optional but the A5 buffer tube VLTOR makes (BCM makes one as well) is a nice upgrade as you can use a rifle length spring in a tube that's only slightly longer than a standard carbine tube.
I believe i use a standard carbine tube, what would be the benefit of using the longer tube with longer spring? A vs H is that to do with the dimensions or weight?
 

Dfalt

Established Member
Mar 13, 2021
786
929
Troy, AL
The A in the A5 in this case is just the name of the tube; VLTOR originally designed it for the Marines so they could keep the performance of a rifle length buffer spring from their M16A4s in the same approximate form factor of an M4 carbine tube. A rifle length spring is longer therefore it can absorb more force from the bolt leading to lighter recoil and less wear on the gun.
 

JT300

Smooth Brain in Alabama only local preferred
Jun 2, 2022
203
94
Calera AL
The A in the A5 in this case is just the name of the tube; VLTOR originally designed it for the Marines so they could keep the performance of a rifle length buffer spring from their M16A4s in the same approximate form factor of an M4 carbine tube. A rifle length spring is longer therefore it can absorb more force from the bolt leading to lighter recoil and less wear on the gun.
is there a kit of this to buy to insure all measurements are correct if not the tube and i will get spring and weight separately. I imagine the same braces/stocks will work with these tubes.thanks
 

Dfalt

Established Member
Mar 13, 2021
786
929
Troy, AL
Yep you can buy kits with everything together, and any mil-spec carbine stock will also fit on an A5 buffer tube
 

LatterVersion

Established Member
Dec 14, 2021
11
6
Huntsville
The best way to approach this is with adjustable gas blocks, not the buffer. The more reciprocating mass, the more muzzle movement you will have during operation. Using adjustable gas blocks you can dial both in using a standard carbine buffer. I always shoot suppressed now, so I just set my upper to cycle with the weakest ammo I plan to shoot and then it will run anything.

Heavier buffers are good if you are having bolt bounce or timing issues. They will also slow your timing down and give some extra inertia to chamber rounds into dirty chambers. If you keep your guns clean and set the gas system up correctly, they will run great with a milspec BCG and carbine buffer.
 

JT300

Smooth Brain in Alabama only local preferred
Jun 2, 2022
203
94
Calera AL
The best way to approach this is with adjustable gas blocks, not the buffer. The more reciprocating mass, the more muzzle movement you will have during operation. Using adjustable gas blocks you can dial both in using a standard carbine buffer. I always shoot suppressed now, so I just set my upper to cycle with the weakest ammo I plan to shoot and then it will run anything.

Heavier buffers are good if you are having bolt bounce or timing issues. They will also slow your timing down and give some extra inertia to chamber rounds into dirty chambers. If you keep your guns clean and set the gas system up correctly, they will run great with a milspec BCG and carbine buffer.
Im looking at a bleed off gas block superlative arms i believe but also may trade my 556 upper for a midwest industries 8in blackout upper not sure how well it will be gassed as i do not know much about midwest industries. anyone like them?
 

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4l65e

Established Member
Apr 30, 2023
26
16
Alabama
I know this is an older thread, but I've had pretty good luck with just a standard carbine weight buffer and spring set with an 8" .300 Blackout. I wouldn't worry too much about special spring rates or buffer weights until you start having issues, then you can tune it.

Midwest Industries is good to go, I'm sure you'd be happy with that upper. I didn't see a gas port size listed on their website, but I bet it would work just fine with the carbine spring and buffer you already have.
 
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