A1 Recoilless Stock

Talk about the AR15 style rifles chambered in 450 Bushmaster.

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A1 Recoilless Stock

Postby dantheman » Mon Jan 23, 2017 8:27 am

Howdy,

I'm hoping to recreate one of gunnut's A1 Recoilless Stocks next week. I know in the A1 stock there was only one recoil reducer.

If someone owns one of these stocks, do you remember the location of the recoil reducer?
I know many feel that a recoil reducer should be installed as close to the comb as possible but many are placed in bolt holes of shotguns in the center of the stock. Where did gunnut place them?

Any guidance one could offer would be appreciated.

Thanks,

Dan
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Re: A1 Recoilless Stock

Postby Hoot » Mon Jan 23, 2017 11:14 am

Dan, I suspect the location is more about whether you want to access it via the trap door or not. Ideally, the weight would be up close to the buffer tube as is physically possible, but that may not be consistent with accessing it through the trapdoor. The most important aspect of the hole is to make it parallel to the barrel, not angled above or below that plane. If one had an accelerometer setup and an unlimited supply of stocks, one could experiment with vectoring the force to see if that provided any improvement in perceived recoil.

I never found it to be a life changing effort to remove the butt pad, so I cast the holes in my two, as close to the buffer tube as possible. Also, I was able to cast two holes in an A1 stock. Assuming you're going to buy a commercial "shake weight" reducer like an Edwards, they list the various lengths available as well as the diameter. Ditto on the Dead Mule made by Ballistic Products. There are several other brands out there.

I wound up rolling my own reducers along with custom diameters, so that's about all I can advise you on. I prepared the inside of the stocks by roughing them up to produce a good bonding surface and degreasing before casting the 2-part into them.

Hoot
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Re: A1 Recoilless Stock

Postby dantheman » Mon Jan 23, 2017 12:07 pm

I bought a Dead Mule online. I used the A2 butt plate to modify the recoil pad.

So keeping the recoil reducer close to the buffer tube is best to mitigate the recoil. I wonder if locating the recoil reducer in the center would give the recoil pad further support, being the reducer will be a snug fit with the use of rubber grommets like I've seen in the x-ray photo of gunnut's stock. Then the support for the recoil pad would be more even....not just supported from the toe and the heel of the stock. Recoil mitigation may not be as efficient with a center location but it will still work decently as evidenced by the many positive reviews of gunnut's stock..

Decisions. decisions...

Dan
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Re: A1 Recoilless Stock

Postby dantheman » Thu Feb 02, 2017 7:24 pm

Here's some of the progress I've made attempting to recreate one of gunnuts A1 Recoilless Stocks.

I first made a jig out of some scrap wood and a 1" dowel. The dowel went through the buffer tube hole in the stock. I scrubbed the interior of the Cavalry Arms C1 stock with Acetone. After that dried I roughed up everything I could with a wood rasp and then scrubbed with acetone again.

I used an aluminum rod that is 12" long and 15/16's round. I drilled two holes through it. One towards the top so I could insert a screw driver through the rod so I could remove the rod from the stock. The other hole was drilled through at 5 inches. I put a pistol cleaning rod though that to suspend the rod in the stock. This created a chamber for the Dead Mule recoil reducer of 4.5 inches. I coated the rod with 2 applications of Hornady One Shot case lube and then put a coat of clear shoe polish on top of that as a release agent.

I used a 50/50 mixture of Bondo Fiberglass Resin and Microspheres. I poured half of the stock first and then let it set for about 15-20 minutes. Then I poured the rest of the stock. This is because of the heat generated by the resin curing (exotherm). If one's not careful, a large amount of resin could literally start a fire because it can get so hot. The microspheres cut down some of the exotherm as well. So it's best to pour the resin in two steps.

I waited about an hour and removed the rod...it was a very tight fit. It made a champagne cork popping sound when it was removed.

I know I'm going to have to grind some of the resin near the toe area of the stock because it's a little high there and the recoil pad won't seat correctly. I'll do that in two or three days, everything should have totally set up by then.

Here's some photos...

Image

Image

Image

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Dan
Last edited by dantheman on Fri Feb 10, 2017 7:14 pm, edited 1 time in total.
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Re: A1 Recoilless Stock

Postby Hoot » Thu Feb 02, 2017 8:17 pm

Way to go Dan. I wish more of our the members would do more experimenting and write it up. It keeps this from being too much a Customer Support site and one more given to sharing ideas. They don't have to be Nobel Prize material, but they can serve to keep interest juices flowing, by stimulating thinking outside the 9 dots. John was kind enough to share his ideas about reciprocating weight with us. It sure got my curiosity flowing as I always thought the best kind of weight was dead weight. It immediately stimulated me to experiment with different solutions along that line of reasoning. At the time I was doing this, John was actively trying to sell products implementing his ideas, so I didn't publish my work. Now that he is no longer able to pursue that business interest due to the health impact it had upon him, he would I'm certain, be proud of our continuing quest for improvement.

Many will be quick to venture the fact that the 450b recoil is not punishing and compared to many calibers it truly isn't. That's not the only reason for pursuing different avenues of recoil reduction. At the very least, it is interesting in trying to mitigate recoil. That was a compelling argument for the GyroJet cartridge. That didn't work out so well as a commercial success, but it looked outside the 9 dots.

It also got us thinking more about continuous process improvement not just being content with dogmatic solutions.

Hoot

P.S. Smart move reinforcing the channel through which the receiver extension tube passes to make sure that pressure didn't distort it. -and- It's OK to resize your images before publishing them. I usually shoot for 800x600 ;)
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Re: A1 Recoilless Stock

Postby dantheman » Thu Feb 02, 2017 9:34 pm

I must say that you gentlemen have been an inspiration for me, taking me a bit out of my comfort zone with some "shade tree" gunsmithing and trying a few new things. I've always been good with glass bedding bolt actions and shortening a screw here or there, refinishing a stock, etc.

I'm enjoying learning some new techniques...especially with an AR platform.

Dan
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Re: A1 Recoilless Stock

Postby dantheman » Thu Feb 23, 2017 7:16 pm

I finally got a chance to shoot the rifle today with the A1 Recoilless stock and the Ross muzzle brake.

It was a beautiful day in upstate NY. Around 70 degrees outside! The snow was melting before my eyes.

I shot my 450 next to my friends new 6.8 SPC build. I'd say that the recoil was about the same as the 6.8 SPC.
The only difference I noticed was that in a t-shirt, I could actually feel the Kick-eez recoil pad squish against my shoulder a little. So it works well.

His 6.8 SPC had an A2 buttstock and a non-threaded barrel.

Dan
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Re: A1 Recoilless Stock

Postby Hoot » Thu Feb 23, 2017 9:13 pm

Dan did you try shooting slightly uphill and downhill to see if the mercury pre-positioning forward or back had any effect on the recoil? I often wondered if I practiced on level ground, what would happen shooting down from a tree stand?

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Re: A1 Recoilless Stock

Postby dantheman » Thu Feb 23, 2017 9:40 pm

No Hoot I did not. My tree stand days are over.

I had brain surgery 10 years ago to remove an Acoustic Neuroma tumor off of my hearing/balance nerve. I'm completely deaf in my right ear and my balance is less than perfect. That left me physically unfit for duty and I took an early retirement. A normal day for me is having the vision and balance one might have after drinking a couple of beers.

I generally find a big stump or rock to sit on off of a game trail and usually get a buddy to help me retrieve the deer after I shoot them. It's all good, I still love to hunt. I've just have to do things a little differently. That's why I'm anxious to try the 450 Bushmaster for hunting. Dropping a deer right then and there is important to me. Long drags are more difficult these days.

Dan
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