Integral rear cap thoughts

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John A.
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Integral rear cap thoughts

Post by John A. » Mon Nov 26, 2018 6:06 pm

Evening guys.

I'm hoping to get my stamp back any day for my Integral rimfire. They received my sketch back last Friday according to the signature delivery card.

Anyway, it's going to be similar to the gemtech mist. Though obviously with my own changes and touches.

From everything that I have heard, one of the main reasons that they stopped porting the barrel is too many folks waiting too long to clean the can and take everything apart. Apparently, the rear threads get seized up and is damaged or something ?????

While I don't necessarily plan to port my barrel right now, it is an option in the future if/when ammo shortages come down the pike like we have seen several times in the last decade.

So, I've given it a lot of thought of how to address that and have decided that I am going to do a rear cap that doesn't need threads.

The tube will tension in place via the front cap and thus eliminate the need for rear threading altogether for the suppressor tube.

I plan to use a couple of rubber O-rings, plus a sharp angled edge on the rear cap and the tube so once the tube/front cap is tightened down, the tube should mate up well to the rear cap.

It will also be self centering, though I doubt that would really be an issue considering that it will slide over the monocore baffle and all the way over the length of the barrel too. I dont' think there will be a problem containing what little gas the 22 is going to be dealing with.

What do you guys think?

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fishman
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Re: Integral rear cap thoughts

Post by fishman » Mon Nov 26, 2018 6:54 pm

Seems like a solid plan. I'd do the angled edge angled the other way though, just for ease of machining.
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John A.
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Re: Integral rear cap thoughts

Post by John A. » Mon Nov 26, 2018 6:59 pm

I had thought about it, but this angle would seem to make it more difficult to escape given that it would have a sharper bend in it and be supported better on all sides.
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Re: Integral rear cap thoughts

Post by ECCO Machine » Mon Nov 26, 2018 10:09 pm

You don't need to bevel the tube. You really don't even need O rings for .22 LR.

Threads or no, if you port the barrel, you'll have a hard time removing the tube after even a fairly modest round count. Best way to keep it from seizing in the ported area behind the monocore is a split tube within a tube.
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Re: Integral rear cap thoughts

Post by a_canadian » Mon Nov 26, 2018 10:37 pm

Yeah, what he said. A couple of hundred rounds if you did end up porting the barrel at all and the inside of that tube is going to be a mess, very hard to pull over a front guide block as the crud will jam. Especially the crud immediately opposite the ports. Fuses onto the tube rather thoroighly. I'd probably go with an O-ring, use a high temp type, and machine a simple right angle interface between tube and rear block just for repeatability. Don't want it gradually eating itself with repeated cleanings and re-mountings. A split tube held in place as you slide the main tube over the barrel shouldn't be hard to arrange, again with simple steps turned into the blocks at either end to seat it. Something like 0.025" wall stainless would last forever and be easier to clean.

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Re: Integral rear cap thoughts

Post by John A. » Mon Nov 26, 2018 10:54 pm

I have a few 1" o rings that I planned to use in my shop already so I'm not out anything but a few minutes using the cutoff tool to notch out the parts, and while I assumed they may be over-kill, had planned to use them to further help tension the outer tube, from a lack of better explanation I guess.

Where does the fouling/buildup occur mostly that gives the most problems? I assume directly over the monocore ??? I'm just not certain if I can put a clamshell over the monocore baffle or not with my numbers, although I'm sure that would be ideal.

As for if/when I port the barrel, I was going to make the rear endcap long enough that when it is in position, it would be hollowed out and covering where the port was going to go on the barrel so any buildup from the barrel port would be jetting into the underside of the thick rear cap rather than directly inside of the suppressor body. I would think that would negate the need for a clam shell over the barrel behind the monocore. And would save some weight too.

But I welcome any suggestions that you may have to make it better or just tell me if I'm wrong.
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Re: Integral rear cap thoughts

Post by a_canadian » Mon Nov 26, 2018 11:38 pm

Nothing wrong with the latter idea. An extended hollow section giving at least an inch of overlap ahead of the ports should help keep.the tube scorching to a minimum, if any. But there's still the glassy, filthy crud. I've done a couple of integrals with ports, and have found them difficult to slide apart after a hundred shots. That primer glass really scrapes into 6061 badly and I'd expect similar abrasive effects on any aluminum tube. Seems a thin clamshell over both monocore (slightly reduced diameter for the clamshell, starting just before the initial space and ending just after the last), and over the ported barrel section (if/when you do that) are the only way to make it slide apart easily without scraping the tube to hell every time you clean it.

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Re: Integral rear cap thoughts

Post by gunny50 » Thu Nov 29, 2018 7:07 am

John A. wrote:I have a few 1" o rings that I planned to use in my shop already so I'm not out anything but a few minutes using the cutoff tool to notch out the parts, and while I assumed they may be over-kill, had planned to use them to further help tension the outer tube, from a lack of better explanation I guess.

Where does the fouling/buildup occur mostly that gives the most problems? I assume directly over the monocore ??? I'm just not certain if I can put a clamshell over the monocore baffle or not with my numbers, although I'm sure that would be ideal.

As for if/when I port the barrel, I was going to make the rear endcap long enough that when it is in position, it would be hollowed out and covering where the port was going to go on the barrel so any buildup from the barrel port would be jetting into the underside of the thick rear cap rather than directly inside of the suppressor body. I would think that would negate the need for a clam shell over the barrel behind the monocore. And would save some weight too.

But I welcome any suggestions that you may have to make it better or just tell me if I'm wrong.
John solid idea, on the O-rings and bevel. Bevel i snit needed but a nice machining touch.

For the connector solution, if you would port the barrel.
There is a great "old solution for that and it even delays the gasflow more.
Take a look at the "De Lisle Silenced Commando Carbine"
The muzzle device "diverter" they used was a great solution and a real benefit is gasflow.
1st picture below is to big but shows the inside really well, Diverter installed on the barrel.

PS a protective slit tube is not that new. makes one wonder how patens are granted sometimes.... :roll:

https://ic.pics.livejournal.com/nikolaj ... iginal.jpg

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John A.
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Re: Integral rear cap thoughts

Post by John A. » Thu Nov 29, 2018 1:15 pm

This is my first integral rimfire, so I wasn't exactly sure what to expect and I tend to try to over-design everything, but if the bevel isn't needed as several has mentioned, then I can just make a square butt if that will work and be adequate.

Capt. Link gave me a good idea about using .001-.004 stainless steel shim stock sheet to wrap around the monocore baffle in lieu of using thinwall tubing clamshell, which I both didn't have the extra space to accommodate, and/or would've eaten into the area that I have available to use for my chambers.
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Re: Integral rear cap thoughts

Post by ECCO Machine » Thu Nov 29, 2018 3:43 pm

John A. wrote: Capt. Link gave me a good idea about using .001-.004 stainless steel shim stock sheet to wrap around the monocore baffle in lieu of using thinwall tubing clamshell, which I both didn't have the extra space to accommodate, and/or would've eaten into the area that I have available to use for my chambers.
The issue with doing that is keeping the really thin shim stock from crumpling when you slide the tube off. There's no support for it in your blast area, so it's going to deform and get carbon buildup behind it. When you try to slide the tube forward, that carbon buildup is gonna grab that shim stock and mangle it. Now, if you split tube or clamshell the blast area and then use shim stock over the monocore, you'll probably have a workable design. I would definitely go a bit thicker, though, like .005"+ and form the shim stock on a mandrel so it has some shape and integrity.
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John A.
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Re: Integral rear cap thoughts

Post by John A. » Thu Nov 29, 2018 3:53 pm

I had already planned to use a rubber o ring in front and aft of the monocore already. And I was going to put the shim stock between them and obviously roll it around the monocore and only have one slit, much like a wire loom in your car wiring from a lack of better description. I think the o rings will keep the shim stock in position while the tube would be sliding off ?????

I think Capt. also recommended larger than .001 already too which I also thought was too thin, and I was thinking probably .002 or .003 since I doubt there would be enough of a gap between the two parts to go much thicker.

Basically, I was expecting the shim stock to remain on the monocore until after I removed the suppressor tube and then I could slide it off the front once I removed the front o ring and slide it off the end.
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