u/Rikki-Smedley

Earlier I was looking for cheaper solutions to the additional weight needed for a 5.5" S&W .40 build I had done as the weight was on the light side. I really didn't want to use anything longer than a carbine buffer or spend hundreds on parts. I already had some very inexpensive folding buffer set ups and finally found the solution I believe. Of course it is due to blowback9 and his awesome library of knowledge. Due to only having a 5.5" barrel the estimated required combined bolt & buffer weight for S&W.40 is somewhere above 24.0oz. The potential solutions were adding a heavy CMMG bolt weight from their very affordable set. But that only increased the weight just above the standard medium bolt weight. This combined with a FM RECOIL MITIGATION BUFFER was a perfect solution. But it meant using a longer buffer since my bolt wasn't a short stroke. Finally I found an article on folding buffers on blowback9's website that had listed the KAK HEAVY BOLT CARRIER EXTENSION. Although the setup will be longer. It means my brace still fits snug against the back of the tube and has the added benefit of being foldable now. I'll post images for reference.

I changed the handguard in the images and the longer muzzle device to ensure there was no additional back pressure.

Davidson defense upper

Tactical Kinetics 5.5 inch .40 S&W barrel

80% arms lower

Rise armament Rave 140 trigger

Davidson defense.40S&W bolt

S&B brace

AR Stoner 8.3oz buffer weight

KAK heavy bolt carrier EXTENSION

Chinese folding buffer set up

ABC LPK stuff (anti rotation pins, Ambi safety, bolt catch, forward grip etc)

Mil spec spring

Mil spec tube

Strike grip

Looking for a solution to give the carrier or buffer more weight without extending the buffer tube length. The buffer weight is an 8oz solid and total weight with the bolt comes to just shy of 22oz. I need closer to 27oz.

I recently put this .40S&W build together. Ran flawlessly and seems to be a better round for ejection than the 9mm due to the larger diameter. However I only set this up with 21 1/2 ounces on a solid buffer weight and the buffer is beating the bejesus out of the coin I placed in the end of the buffer. I do on all my buffer tubes to make sure they're not bottoming out badly. What are people's potential solutions that are cost effective? Go for a 308 spring or similar? I want to avoid extending the tube or spending silly amounts on buffer weights.

Thanks for your input.

Tactical Kinetics 5.5 barrel

BCA 3.5lb trigger

BCA grip

Davidson defense upper/BCG/buffer tube/handguard

Romeo optic

eBay muzzle brake

AR Stoner 8.2oz buffer weight

AR Mil spec spring

I was tidying up the gun room the other day and realized the extent of my addiction. It might be time to get rid of some double ups soon. I've built all of these bar two.

I'm looking for sources of decent cerakote and powder coat for quantities around 16oz or less. My wife bought me some online with a kit which has been great. But the powder coat is not hard enough with some brands and seems too soft and fairly easily scratched. Or possibly I'm doing something wrong? Prep is washing down with parts cleaner and bead blasting. These packs say to bake 10min at 400. Photos of what I've played around with so far.

After looking at these online for a while I'm considering buying the upper and lower receivers and putting my own together. Has anyone got experience with them? It looks like a great solution for a cheaper all purpose hunting rifle.

FM PRODUCTS 16" (CARBINE) 7.62X39 RANCH RIFLE

I built this for my uncle to coincide with his 60th as he's wanted one for some time and loved the look of the powder coating on my AR47 build (the same color).

Threw in a QD 2 to 1 sling, a box of green tips, box of hornandy 68 grain hollow points and about 100 rounds of 223 62 grain ball ammo, Some QD mounts and a book of range targets.

Build list as follows

Ballistic Advantage stainless QPQ coated bore, fluted, 1:8 twist 223 Wylde 16" SPR barrel.

Aero Precision NOLO BCG

Rise armament RA-100 2 stage 1.5lb 3lb trigger group

Panhead upper receiver

80% arms lower receiver

BCM trigger guard

Trinity force 15' grip

UTG polymer dust cover

Davidson defense stock

Griffin QD endplate

Davidson defense extended mag release

United defense charging handle

Half birdcage semi compensator

BCA 15" handguard

Dirty Bird Ambi safety

All in all about a $800 build and 3 hours work including machining and powder coating.

I built this for my uncle to give him on his 60th as he's wanted one for some time and loved the look of the powder coating on my AR47 build (the same color).

Threw in a QD 2 to 1 sling, a box of green tips, box of hornandy 68 grain hollow points and about 100 rounds of 223 62 grain ball ammo, Some QD mounts and a book of range targets.

Build list as follows

Ballistic Advantage stainless QPQ coated bore, fluted, 1:8 twist 223 Wylde 16" SPR barrel.

Aero Precision NOLO BCG

Rise armament RA-100 2 stage 1.5lb 3lb trigger group

Panhead upper receiver

80% arms lower receiver

BCM trigger guard

Trinity force 15' grip

UTG polymer dust cover

Davidson defense stock

Griffin QD endplate

Davidson defense extended mag release

United defense charging handle

Half birdcage semi compensator

BCA 15" handguard

Dirty Bird Ambi safety

All in all about a $800 build and 3 hours work including machining and powder coating.

Looking for options to replace the bolt with something machined for a 7.62 like the one on the left with a thicker collar. I haven't been able to find anyone selling just the bolt online.

My latest build. First groups at 100 yards once the scope was set mostly. Impressed.

I often see people asking for help with their gas issues (😂. Sorry had to) So after who knows how many builds I have a few of my own pointers on over/under gassing. Here are three examples of under/over gassing on some of my builds.

They can have different fixes depending on what set up you have and/or what is causing the issue. It can be buffer weight, BCG weight, shorter barrels, longer barrels, gas tube length, Suppressed/unsuppressed, hotter rounds, grain count on finely tuned rifles and likely more.

I've also included some charts to help people.

The FDE image is of marks left by rounds ejected almost completely rearward. This would imply heavy under gassing. The barrel is a 10.5" so likely has less restriction and less back pressure. If this had a deflector you may not notice how severely the casing is traveling backwards and may even think it's gassed correctly because of the appeared trajectory after contact. However marks on your deflector are a sign of your gassing not being optimal. It pays to run a range of rounds before making a decision as obviously this can have a major effect. The hotter the round the more gas. So this issue I fixed by running slightly hotter rounds (more gas produced) as I was only running 223 55g for this test run. And using a slightly lighter buffer weight. This was on a complete NBS upper, so don't rely on the manufacturers to get it right out of the box for your set up.

The other shows deflector image shows minimal contact on the deflector. This was likely due to the grain and the round type. This was caused running 223 55 grain in a Wylde mid length gas 16" barrel. Using hotter 556 rounds does not have this effect. No changes necessary, just running what I would be most predominantly running anyway.

The shot of the Lupua 308 round shows severe ejector strike marring. Unlike NATO 5.56/223 the 7.62/308 it is the domestic rounds that are higher powered so I was unlikely to cure this with different rounds.

This was causing ejection issues on a 16" Ruger SFAR with the gas adjusted to mid range on a pre-owned AR10. When dialed down it failed to eject completely. The solution for this was a slightly heavier buffer weight. This reduced the effects of the gas action causing damage to the spent rounds.

Hope this helps some people with their gas issues 👌🏻😂💨