Interesting .22LR Micro Can build...

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cms81586
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Interesting .22LR Micro Can build...

Post by cms81586 » Tue Dec 31, 2013 4:26 pm

Started this last week. It's a short (3" OAL planned when completed) .22LR micro can with 4 K-baffles. The blast baffle has an integrated blast chamber and all baffles snap together. The endcap will be a dual thread concept...both male threads. One end will thread into the can. The other side will accept a part similar to a thread adapter to retain the wipe, should I choose to use one. The tube and endcap are stainless...the baffles are Al. If the K baffles work well I'll scrap the Al and turn some in 304 SS (I work for a SOT on the side building rifles and parts). As you can see I haven't turned the OD on the entire tube. At the blast chamber I plan on externally threading the tube and making a knurled ring to thread onto it. The plan is to mill a small hole through the tube into the blast chamber and through the knurled ring, and then make two detent stops 180* from each other. This will provide a port to introduce an ablative (which will be necessary from such a small can) without unthreading the can from the firearm. It's an odd design but I don't have any money invested in this thing...so it's a fun project and will be interesting to see if it works. The knurled ring should easily contain the pressure in the blast chamber due to the small hole size being utilized. I'll post some completed pictures when it's finished. The tube and baffles still need work, and the endcaps need built. Enjoy!

CMS

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Re: Interesting .22LR Micro Can build...

Post by Enfield577 » Tue Dec 31, 2013 5:26 pm

That is a tiny can.... look forward to hearing how it performs
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Re: Interesting .22LR Micro Can build...

Post by cms81586 » Tue Dec 31, 2013 6:39 pm

When I get to the final version after some testing it will live on a Beretta 21A. It'll be a full inch shorter than the TM Wasp, although a little fatter at a about 0.95" OD. With 4 baffles it "should" be comparable or a little quieter than the WASP when run wet. Wet with a wipe...common sense would dictate K's are quieter than the Wasp's monocore...but I guess we'll find out once I get it finished...

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Re: Interesting .22LR Micro Can build...

Post by mollinst » Wed Jan 01, 2014 11:55 am

I had abandoned using wipes long ago but, they seem to be coming back into fashion again.

Now that we have so many new exotic polymers and materials, what do you feel works the best as a wipe, lasts the longest, etc. Seems to me that I've read about some "self healing" vinyls that may need replacing less often.

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Re: Interesting .22LR Micro Can build...

Post by Baffled » Wed Jan 01, 2014 12:02 pm

Wow, fun project. I've often toyed with the idea of a micro-can as well. We all know going in that it isn't going to be the quietest, but the cool factor is way up there.

If/when I do it, it's going to be as thin and light (Ti) as possible.

I like your notions of adding ablatives and the use of wipes. Since wipes are user-replaceable, there's no reason NOT to include them in the engineering of the can... you can always run it without them. And a half hour's work with a punch will make enough wipes for months of shooting.

How about an interrupted thread pattern for an end cap that holds the wipe(s)? A half-turn and she's off. Like an artillery breech. It'd be smart to find a couple of wavy washers for such an interface to provide a bit of tension on the cap to keep it tight - and maybe a pair of witness marks, tube and cap, that will show instantly if the cap is loosening.

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Re: Interesting .22LR Micro Can build...

Post by MCKNBRD » Wed Jan 01, 2014 12:58 pm

Tagged for future reference. I'm looking at building a small rimfire can, and yours is right around the dimensions I was going for...but I want the OD to be no more than .920"; preferably .875" so it will blend well on my 22/45.

Also, one factor with wipes is accuracy. How much does it hurt accuracy to use wipes? What material is best for accuracy? Inquiring minds want to know!

Keep us posted!
Byrdman

cms81586
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Re: Interesting .22LR Micro Can build...

Post by cms81586 » Wed Jan 01, 2014 1:47 pm

I'll be testing the tube/baffles in a week or so once finished. I'll test it dry and wet...wipes and none. Going to start with some vinyl at first for wipes and see what else it out there as well. I'm not sure what kind of affect the wipe will have on accuracy. Obviously it's not going to produce tack driving accuracy, but from what I've witnessed on other wiped .22LR cans, it's good enough for 15-20yd shots on cans. If the baffles disappoint, I'll try milling out a monocore and see how that goes.

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Re: Interesting .22LR Micro Can build...

Post by CThomas » Wed Jan 01, 2014 1:58 pm

Liking the concept but any concern over the ablative that gets introduced in this way obstructing the bullets path?

As far as the wipes impacting accuracy I know Jim DeGroat passed along a few points in a old thread about shooting 22LR through the NANO

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Re: Interesting .22LR Micro Can build...

Post by cms81586 » Wed Jan 01, 2014 2:17 pm

CThomas wrote:Liking the concept but any concern over the ablative that gets introduced in this way obstructing the bullets path?

As far as the wipes impacting accuracy I know Jim DeGroat passed along a few points in a old thread about shooting 22LR through the NANO
I'll likely go with a 1/8" port into the blast chamber and use a syringe and water. If performance is good enough I can leave it as is. It would be an issue with gel or grease at that size though. If it doesn't give the suppression I'm looking for I'll keep increasing the port size with trial and error until I start getting gases leaking or the hole is large enough that I can add a different ablative. If I can get the hole large enough (maybe 1/2" without issues) then I'll start trying to introduce grease or gel. That should be plenty large enough to ensure the bore is clear...and the little 21A and its tilt barrel design makes it easy to check before loading and firing. Going to try getting it finished on Friday. I'll add the mouse cuts and dater holes and make a new endcap. I had one completed and ready to thread but I accidentally crushed the darn thing getting it unthreaded from the tube. I'll go a little heavier than .050" wall thickness for the "wipe holder" next time around and add wrench cuts before threading for easy removal. More pics to follow.

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Re: Interesting .22LR Micro Can build...

Post by twodollarbill » Wed Jan 01, 2014 4:14 pm

Something that small...adding in a end whip willl be a plus.
My smallest can is a 9mm Hush Puppy with whips.
I still hit everything I am aiming at. :mrgreen:

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Re: Interesting .22LR Micro Can build...

Post by cms81586 » Thu Jan 02, 2014 9:56 pm

More progress. The dimples on the endcap will be gone after I turn it to about 1/2 its current width. They're just for ease of removal after life fire testing. I'll likely mill a slot or make a spanner wrench hole. The baffles all have a .280" bore and the endcap has a .320" bore to allow for some yaw as the bullet passes through the wipe. I altered the endcap design from what I had originally intended. It will still allow for the use of wipes, but requires endcap removal to replace. I want to get an idea of how it will sound wet and wiped before I go about spending 2-3 hours building the part. That's also the reason for the aluminum endcap. Once I get it tuned in I'll go to a stainless endcap. The rear endcap, which will be threaded for the muzzle, IS going to be stainless. Once I hear how it sounds I'll go ahead and mill the ablative port and thread the ring which will cover the port. OAL ended up being 0.10" longer than the the 3.0" I envisioned, but I have a specific size I want the blast baffle. Progress is slow but progress is progress.... Enjoy!

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Re: Interesting .22LR Micro Can build...

Post by Bendersquint » Thu Jan 02, 2014 10:58 pm

Why did you choose a .280 bore for the main aperture?

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Re: Interesting .22LR Micro Can build...

Post by Grounded » Thu Jan 02, 2014 11:45 pm

It would be big enough for a 21A in .25acp as well I suppose
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Re: Interesting .22LR Micro Can build...

Post by doubloon » Fri Jan 03, 2014 12:00 am

looks slick ... will be interesting to hear
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Re: Interesting .22LR Micro Can build...

Post by cms81586 » Fri Jan 03, 2014 12:10 am

Bendersquint wrote:Why did you choose a .280 bore for the main aperture?
3 reasons really.

1) I'm new at this.
2) Started by rationalizing that it was the same bore diameter on the AAC Pilot I have....(which will likely make its way to you some time for a recore since it's got 25k+ rounds through it and is loud as hell with anything other than subsonic ammo through a rifle.) Then considered going smaller than .280 but wanted some room for tolerance stacking since again...I'm new at this.
3) I was concerned with the ability of a 21A to completely stabilize a bullet since it has such a short barrel. Again...probably unfounded and it's never keyholed without a can...but I wanted to play it safe.

Everything is in "rough" stages right now. If this works out well and sounds good I'll refine the machining marks and fit/finish. If it's loud (which I expect it to be before some changes to the design and trial/error testing) I'll continue to chase Db's. I plan on testing before messing with a blast chamber access just to see how it sounds. AFAIK, there aren't any cans this size on the market...and there's probably a good reason for that. It may be a neat option for rifles and subsonic ammo though. We'll see how it plays out this weekend. I'm going to try and finish a rear endcap tomorrow and I gotta run down some vinyl and go from there.

CMS

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Re: Interesting .22LR Micro Can build...

Post by Bendersquint » Fri Jan 03, 2014 12:19 am

cms81586 wrote:
Bendersquint wrote:Why did you choose a .280 bore for the main aperture?
3 reasons really.

1) I'm new at this.
2) Started by rationalizing that it was the same bore diameter on the AAC Pilot I have....(which will likely make its way to you some time for a recore since it's got 25k+ rounds through it and is loud as hell with anything other than subsonic ammo through a rifle.) Then considered going smaller than .280 but wanted some room for tolerance stacking since again...I'm new at this.
3) I was concerned with the ability of a 21A to completely stabilize a bullet since it has such a short barrel. Again...probably unfounded and it's never keyholed without a can...but I wanted to play it safe.

Everything is in "rough" stages right now. If this works out well and sounds good I'll refine the machining marks and fit/finish. If it's loud (which I expect it to be before some changes to the design and trial/error testing) I'll continue to chase Db's. I plan on testing before messing with a blast chamber access just to see how it sounds. AFAIK, there aren't any cans this size on the market...and there's probably a good reason for that. It may be a neat option for rifles and subsonic ammo though. We'll see how it plays out this weekend. I'm going to try and finish a rear endcap tomorrow and I gotta run down some vinyl and go from there.

CMS
Nice explanation, thanks!

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Re: Interesting .22LR Micro Can build...

Post by cms81586 » Fri Jan 03, 2014 12:39 am

doubloon wrote:looks slick ... will be interesting to hear
I'll charge up the HD camera. BTW...your avatar is very distracting... :lol:


I'll take some better pics with the wife's work camera soon. I'll just have to prepare for the critique on my machining skills (non-existent) which my potato camera phone has kept partially hidden thus far.

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Re: Interesting .22LR Micro Can build...

Post by cms81586 » Fri Jan 03, 2014 9:52 pm

Got the endcap done today. Need to trim a baffle, clean up some exterior machining... and finish the baffles. Got a ball end mill tool on order for the mouse holes and will do the dater hole(s) at the same time. Might get to do some initial testing on Sunday.

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Re: Interesting .22LR Micro Can build...

Post by delta9mda » Sat Jan 04, 2014 1:07 am

please scoop the baffles or else it wont work well at all.

that said cool concept.
NP

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Re: Interesting .22LR Micro Can build...

Post by cms81586 » Sat Jan 04, 2014 1:28 pm

See post above. Tooling is on the way.

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Re: Interesting .22LR Micro Can build...

Post by CThomas » Sat Jan 04, 2014 1:56 pm

cms81586 wrote:Got the endcap done today. Need to trim a baffle, clean up some exterior machining... and finish the baffles. Got a ball end mill tool on order for the mouse holes and will do the dater hole(s) at the same time. Might get to do some initial testing on Sunday.

Are you planning on doing a "dater hole" in more than one baffle?

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Re: Interesting .22LR Micro Can build...

Post by cms81586 » Sat Jan 04, 2014 6:42 pm

Really not sure. Ill definitely go with one on the blast baffle. I may make a few others with Dater holes to try out throughout the stack, but the can is so abbreviated I'm not sure that it'll be beneficial.

CMS

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Re: Interesting .22LR Micro Can build...

Post by jlwilliams » Sun Jan 05, 2014 8:41 am

Exciting project.

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Re: Interesting .22LR Micro Can build...

Post by Historian » Sun Jan 05, 2014 9:51 am

cms81586 wrote:I'll be testing the tube/baffles in a week or so once finished. I'll test it dry and wet...wipes and none. Going to start with some vinyl at first for wipes and see what else it out there as well. I'm not sure what kind of affect the wipe will have on accuracy. Obviously it's not going to produce tack driving accuracy, but from what I've witnessed on other wiped .22LR cans, it's good enough for 15-20yd shots on cans. If the baffles disappoint, I'll try milling out a monocore and see how that goes.
Thank you for sharing this interesting project.
Being an impatient reader did I miss the diameter of the can
somewhere?

Your design does bring up a question that I have not seen mentioned ... given
your final constant volume for the can, would making a can say 1/3 the diameter and
longer with more K-s decrease db's? Intuition says most likely but does anyone
have empirical data?

As for wipes a candidate you might consider is silicone cooking pads from
say William Sonoma. The thickness is in the range of the wipes once seen
in a Chi-Com SMG; easy to cut by tracing around the end of a pressed K, and it
handles high temps easily ... no burned kitchen counters, etc.

Really nice shots.

Best.

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Re: Interesting .22LR Micro Can build...

Post by CThomas » Sun Jan 05, 2014 1:02 pm

Historian wrote: Thank you for sharing this interesting project.
Being an impatient reader did I miss the diameter of the can
somewhere?
Best.
0.95" OD in OP's 2nd post

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