I have an XRT all-stainless kit. It has the 1.025” ID  6” tube and uses 60-deg cones with click-together skirts.  Looks very similar to SicencerCo Warlock/Spectre type baffles.  My baffle spacing will be variabl; .400-.560"

The the longer spaced baffles will be at the front of the stack with a bore of .255” and the intent to be used as interchangeable blast baffles and the the .400” skirt baffles make up the rest of the stack with a planned .266” bore on those. Baffle clipping TBD.

Total baffle count will be somewhere around 10-11... but that depends on the blast baffle spacing... so my question is: how much spacing should I have between the muzzle and the tip of the first cone?

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EDIT:  OK, following the advice here I'm going with blast baffle spacers that put the thread shoulder about 1.000" from the blast baffle cone meaning the cone-to-muzzle distance is .450-.550" (depending on the host firearm thread length).

Next question... clipping. After much reading I've decided to clip the first 3 "blast" baffles with two cuts and the remaining 7 baffles with a single cut.  But what should be the dimensions of the cutouts?  My Warlock II has a single clip that measures 0.185"W X 0.145"D... Is there better clip dimensions for single-clipped 60-deg cones? Do two symmetric clip cuts get the same dimensions as singly clipped baffle cuts, or are the two cuts reduced somehow since there's two of them?

Finally, are these tube walls significant enough to handle heavy fire - full auto rated?  The 304 stainless tube in the kit as received from XRT has ~0.022" thick walls in the thinned out portion and the baffle skirts are only 0.020" thick.  Even shallow engraving could cut like 25% of the way into the wall

See new illustrations (click for giant picture):

   

forget the popular measurement but its not much or you will have more first round pop.

0.4 to 0.6” is a good range. A tight blast baffle may not be any quieter and could impact stability, just something to test early on.  Double clipping the blast baffle can also be useful in helping with first round pop.  A lot depends on your host and ammo.

Planned hosts are a Ruger bolt action and a 22LR AR kit... if I can get it working reliably with the full auto. It might get tossed on a 5” pistol occasionally, but I have other lightweight more compact cans for that.

I was only going to do .255 inches for the first two or three baffles. Then I heard that .265 is pretty popular for all the baffles. The work is being done in an actual machine shop on a real large so I’m not too worried about concentricity. I could have machine the whole thing from barstock myself to save some money, but the price that XRT charges for these pieces, and they are phenomenal looking parts with great consistency, it just makes sense to finish the kit myself rather than spend several hours.

1/2" spacer is what I've done and recommended. Results are rewarding.

I'd listen to KP's advice. You don't want your BB too restrictive, especially on a blowback action.

Primary host as mentioned is a bolt gun.  So I'm not too worried about backpressure or weight/size on this one. These will be dial indicated and manually lathe-bored... I expect baffle bore true position and concentricity to be <0.001" so a ~255" bore for a .224" bullet should not be close at all to giving any strikes interference if XRT made their thread cap and tube parts accurately.  The remaining baffle stack can be .266" as that's pretty common even for commercial cans.  I can always make any bore bigger if needed.

UPDATED OP:  OK, following the advice here I'm going with blast baffle spacers that put the thread shoulder about 1.000" from the blast baffle cone meaning the cone-to-muzzle distance is .450-.550" (depending on the host firearm thread length).

Next question... clipping. After much reading I've decided to clip the first 3 "blast" baffles with two cuts and the remaining 7 baffles with a single cut.  But what should be the dimensions of the cutouts?  My Warlock II has a single clip that measures 0.185"W X 0.145"D... Is there better clip dimensions for single-clipped 60-deg cones? Do two symmetric clip cuts get the same dimensions as singly clipped baffle cuts, or are the two cuts reduced somehow since there's two of them?

Finally, are these tube walls significant enough to handle heavy fire - full auto rated?  The 304 stainless tube in the kit as received from XRT has ~0.022" thick walls in the thinned out portion and the baffle skirts are only 0.020" thick.  Even shallow engraving could cut like 25% of the way into the wall

See new illustrations (click thumbnails for giant picture):

   

i asked and it was said that 556/223 could be handled with these... i have a swr spectre that.... didnt... so, try it if you "brave"?

The XRT 60-deg cones themselves protrude about .385", so putting a 1/2" spacer would leave the tip of my blast baffle cone only about .115" from the muzzle (depending on length of host barrel threads)... or .615" from the shoulder, depending on how you ant to look at it.  That can't be right, can it?  I could probably swap the one .400 spacer out for an extra .400 baffle... I bought extra from XRT in case I mess some up (cheap insurance).  In fact, the .400 spacer is MADE from cutting the cone off of one of he spare solvent trap cups.

Also, I just used a depth gauge on my SiCo Warlock II and the blast baffle cone tip is exactly 1.0005" from the shoulder with the endcap having a built-in .785" spacer... and the Warlocks/Spectres are not considered to have FRP.


Thanks for the clipping  tip!  1/8" is pretty convenient.  Lots of tool choices (ball mill, flat endmill, radiused tip endmill, arbor cutter...).  Are both clips on a double-clipped baffle still going to follow that rule of thumb for width and depth?

CAD image is 100% accurately modelled... endcaps have very thin shoulders, too small/short to engrave on. The non-dogboned section is actually still only about .021" thick walls between the larger diameter OD portion and internal thread root.  As for engraving one of the endcaps, they both have dumb unnecessary designs on them.  I'm actually considering taking the threaded endcap and turning the shoulder completely flat because that raised section at the thread shoulder is not only dumb looking no matter what gun you put it on, it reduces the frictional bearing area of the shoulder.

Your not going to want a whole lot more than 1/8" spacing between tip of cone to muzzle.  If you go with that .5" spacing, you could get some FRP.  I built an XRT can and went with the .390 spacer between adapter and first cone.  So there's less than 1/8" between tip of cone and the threaded portion of the front cap.  I haven't had any perceivable FRP and it's much better than the commercial can I have.

1st post from SE PA. Sorry for the long winded inquiry. I'm looking for the mystical  XRT spreadsheet.

After being a lurker. I made the plunge and joined this amazing community (gold member). To say that the wealth of knowledge within this forum is almost overwhelming, is an understatement!

As a home builder for the majority of my pew pews,  I recently dove into the Form 1 rabbit hole for cans. Man, I still have a TON to understand. Probably like most, I'm starting with a 22lr.  This is for a dedicated CMMG build which will have a fulltime can on a 4.5" barrel. I'm still waiting on the majority of parts.

With that said, I have decided to use XRT. In preparation for that build, I reached out to @number40fan to inquire about his jigs, alignment tool and clipping guide.

This is where I could use some serious help! Since the silencer site was tyrannically shut down, I cannot find the XRT spreadsheet to help folks like me. Does anyone have it to share??? I'm having a hell of a time trying to determine which cups and spacer to purchase. I know I will have to do some shaving on my end.

Is there anything else a newb like me should be considering?

Thanks in advance!

@Buckrub71
Is this what you're looking for?

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I was about to share that spread sheet. Lots of good information for ordering the parts.

Thanks...much appreciated! However, I'm still on a learning curve here. If I am reading this correctly, this is for a 5.5" tube which accounts for the end caps internal tolerances, the spacer (blast chamber), initial cup step which seats onto the spacer and then remaining skirts in varying sizes. In this example, there are 10 cups leaving a final tolerance of -0.005. Does this allow for a "tightly seated" internal setup and is this final calculation what I should be looking to mirror?

Since I am going with a 5.9" tube, let the number crunching begin. From what I have found in my research, for 22lr--just as can be seen in this spreadsheet--decreasing cup size as the setup moves toward the distal chamber is better for lower pressure setups (i.e. 22lr, 9mm, etc.). "Better" is defined as having a potential for a greater potential of decreased db. Am I correct? Am I overthinking this?

Below is what I am considering to meet the final tolerance of -0.005 as shown in the spreadsheet. If I am missing something, any and all feedback is welcome and most appreciated!

Proposed 5.9" Setup
5.9" (tube) - 0.400" (adapter) - 0.300" (end cap) - 0.425" (spacer) - 0.060" (first cone step) = 4.715" remaining internal space for determining cup sizes

Cups (10 total)
0.6, 0.56, 0.56, 0.52, 0.48, 0.48, 0.44, 0.36, 0.36, 0.36 = -0.005

Attached File


I used a rimless endcap.  Gives you some wiggle room.

I have done a 5.9 and a 5" and have found no discernible difference in sound in the two.

Thinking about doing a 4.8 as the 5" barely pokes out of the holster on my pistol.

Thanks. Mine will be primarily for a dedicated AR22. I need the little extra length to work with the barrel and handguard configuration. Have any pics???

I can take some later.  Don't have any at the moment.

I left one stainless (1022 stainless host) and painted the other with black hi temp engine paint (required several baking sessions between coats)

They work as well as the Sparrow I have, probably a hair better.

I have a DA Mask in jail, so will be interesting to see how it stacks up against the Form 1's

No worries and thanks.

I've been reading up on paint recommendations. Some require baking and others seem to have success with the Krylon high temp rattle can exhaust paint which doesn't require baking. Jury is still out for me. I've got some time to figure that out though. The all externals are stainless.

The DA has definitely caught my attention on more than one occasion.  I figured I'd cut my teeth via F1  before buying a commercial can.

Thanks again.

The paint I used required baking/cooling cycle a few times.  Seems to be holding up well though.

Will post pics tomorrow.  On the way to a ballgame now and won't be home until late tonight.

Sounds good. Enjoy!

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That’s the 5 inch

Looks great...wouldn't know it a Form 1. Thanks for sharing.

The XRT stuff is awesome. When my buddies saw mine a couple of them immediately wanted one.

They were not impressed with the e-forms website lol