327pd mid project

[bluejeans]

long in the planning, finally in the making.
i haven't been documenting this very well but finally stopped to take some pics today.. thought i'd share some teasers.

the barrel is from a shilen match grade stainless 1-14" blank. (didn't have the camera for that.) all work is on my atlas 12x36" lathe and milling attachment.

lining up centers to make the indexing cut in the shroud:


milling a rough external profile and ejector slot:


sides roughed, ejector rod mortice finished lout with a ball end: (note indexing cut in top.)


test fit:


original barrel for comparison.. i like the 3" so much better.


also notice that the extra length allowed me to switch to a full-length ejector rod.

next up is to cut the final external contour on the shroud and to cut the forcing cone and crown on the barrel.

 

[TruthTellers]

Making the barrel yourself or buying an insert?

 

[bluejeans]

i made it. turned it to the same profile as the original S&W... just made it an inch longer. cut reverse threads on the muzzle end to use the original nut. (made a spanner wrench for that too.)

this is the first of several barrels so i'll get better pics of the whole process next time.

 

[gotboostvr]

Are you gonna leave it kind of monolithic like that?

I kinda like the almost octagonal look that the rough cut has.

 

[Hondo 60]

Wow - you're waaayyyyy better at that stuff than me.
I was the kid in shop that made funny lookin ashtrays.
Even when the project started as a hammer.

 

[bannockburn]

bluejeans

Definitely like the look of the monolithic 3" barrel as well.

 

[bluejeans]

thanks guys.
i want to try the classic S&W barrel contour on this 3"... round on the sides with a rib down the top. for a carry gun i'd like to keep it light and smooth. first i need to make a mounting block for my tool post to hold my unimat so i can hold the barrel between centers and rotate between cut... since i'm too poor to have a rotary table.
when i get around to making the 6" barrel for this i do plan on leaving it blockier.. probably with rails top and bottom.

 

[gotboostvr]

Blue jeans, that's a alloy frame correct?
Why not use a steel frame if you're gonna mount a heavy barrel? It'll be real nose heavy I'd think.
You could mount up a 6" pencil barrel and have a mountain gun concept taken to the extreme

 

[bluejeans]

Blue jeans, that's a alloy frame correct?
Why not use a steel frame if you're gonna mount a heavy barrel? It'll be real nose heavy I'd think.
You could mount up a 6" pencil barrel and have a mountain gun concept taken to the extreme

alloy frame; you are correct.
this barrel however is NOT heavy... the stainless rifled liner is cut to .575 diameter (same as the original) and the shroud is one piece aluminum... very lightweight. i use this gun for my work in the woods all summer so keeping it lightweight is a priority.

once i finish these barrels i will post the finished weight of each length.

now for my 44 mag build i am going to do just as you suggest: start with a 629 stainless frame but for a .357 i think this alloy frame has plenty of strength and the forcing cone, which takes the brunt of the blast, is extra thick due to the smaller bore...

 

[Bula]

All I can say is wow. Very cool.

 

[Panzerschwein]

Excellent.

Should increase the stopping power and accuracy of the gun.

 

[gotboostvr]

Ah, I wasn't aware that was an aluminum shroud.
That does change things a bit.

Very cool projects none the less. Looking forward to the final results

 

[horsemen61]

Any news?

 

[pintler]

Bluejeans: nice work!

I'd be interested in how you disassembled the original barrel. All I know about the shrouded barrels is this:

http://s179.photobucket.com/user/1swchad/media/scan.jpg.html

I thought that drawing implied there were threads on the barrel liner where it goes through the frame, that were just omitted in the drawing. But your picture of the removed original barrel also doesn't seem to show threads. How does the attachment work? Did you get one of the special inside-the-barrel wrenches?

"...cut reverse threads on the muzzle end to use the original nut. (made a spanner wrench for that too.)"

hmmm... that sounds completely different from the picture I linked. Now I totally don't get what keeps the barrel attached :-(

ETA: I found this:

http://s233.photobucket.com/user/se...3-444E-A242-CE20C47D025B_zps7py30vlx.jpg.html

which shows a threaded barrel and nut. Maybe the pic in the OP just doesn't show the threads for some reason?

 

[bluejeans]

Any news?

The news is: I'm halfway done with the 6" barrel and its turning out beautifully! I'm taking care to take a lot more pictures of the process for a good write up.... The non-news is that I'm out of state on a construction project for a month so nothing is happening currently.

 

[bluejeans]

I'd be interested in how you disassembled the original barrel.

Its hard for me to see on my small screen but the diagram you linked appears to be a 2-piece barrel ( liner is threaded for the frame on one end and has a flange on the muzzle end... Uses a special tool which engages the rifling to tighten it in against the shroud.)
The 327 uses a 3-piece design in the the barrel liner is threaded on both ends... Rh thread into the frame and lh at the muzzle... This was the barrel is finger threaded into the frame up to a feeler gauge held on the cylinder to set the b/c gap, the shroud is slide over the liner and then the nut is installed into a recess into the muzzle of the shroud... Tensioning the liner ajd compressing the shroud. Much more user friendly the reverse threads at the muzzle help keep you from messing up the cylinder gap when torquing the nut.

Someday I'll get the rest of the pics up...

 

[bluejeans]

some progress from a couple weeks back on the 6" barrel. i'm layed up right with a broken arm and clavicle so just getting caught up on uploading some pics.

cutting the barrel. it a lot of passes to turn it dow ffrom the 1.25 blank to .560"


asthe diameter shrinks i add the follow rest


threads for the frame end.


learned from the last one... this time i stopped cutting a few thou oversize and pollished is down to spec with 400 grit sandpaper the finished w/ 600... much prettier than tool marks.


milling the t slots in the rail was fun.


profiling the sides.


semi finished. i used a ball mill to make gutter down thw top of the rail in case i ever need to take scope off and use it as a sight. i'll probably drill through the front sight post to add a hi-viz bead.





can't seem to get my camera's flash settings right.


next up is cutting the crowns and forcing cone on both barrels.
i'd appreciate input on the corcing cone angles. i've read a lot but i haven't found any hard data.. just surmisings and opinionations on anything from 5-18 degrees. i shoot a mix of jacketed and cast bullets. i'm currently inclined toward the 11 deg cone just because its in the middle of the numbers i find if anyone has personal experience with various angles or can point me to a good reading source i'd appreciate it.

 

[gotboostvr]

Thanks for the update!
I caught myself wondering about this project while I had some downtime at work today.

The only thing I know about forcing cone angles is that 11° seems to be the most often number that people have them recut to.
Anytime I see mention of someone recutting a forcing cone, it's almost always to get to 11°.

 

[bluejeans]

back on it. i got tired of having one of my favorite guns out of commision.

i had been waiting for a chance to mount my little unimat on the toolpost for properly profiling the barrel shroud and make a cutter for the forcing cone... so instead i made some quick and dirty tricks (warning; all you true machinists will hate me,) to get this project finished and shooting again.

so i positioned a single flute of a 4 flute endmill in my boring bar holder, set the toolpost at 5.5 deg. and used the compound to cut the forcing cone to 11 degrees.




then lapped it.

reduce angle to 0 deg. and crown the muzzle. lap.


use a flap disk on the angle grinder to round off the shroud and spray on some cheap, hardware store black.

 

[bluejeans]

the front sight was a take off from my m&p40 when i went to hi-viz. i had bought a dovetail cutter but now, months later, i discover that i got the wrong angle so i just made a pass with a straight (90) 1/8" endmill then spent 15 minutes with the scroll saw widening the bottom until the sight would enter about a 1/16" then drifted it into place with a hammer and punch. tacky huh? actually it didn't turn out that bad; one wouldn't notice unless you're reeally looking.




then it was time for testing.

armed with calipers, feeler gauge, barrel nut wrench, safety glasses (special for this nervous ocasion) 3 types of ammo (.38 spl, 38 +p, and 357 mag and ear protection i measured everything carefully loaded it up with .38 spl then closed my eyes (not really) and pulled the trigger.
boom.
carefully inspect. remeasure everything. good. fire remaining 7 rounds inspecting gun between every shot.
first 8 rounds of 38 spl.


clean out barrel.
next loaded it with 38 +p and did the same. measurements held and everything stayed tight so i again swabbed out the barrel and then loaded it up with .357 mag 158gr.

here's a shot of my first 3 8-shot groups at 26 feet. both 38 loads impacted 2" low while the .357 mag was dead on... just how i like it. didn't have to regulate the sights at all which was a nice surprise.


that's it for now. once i finish the other barrels i'll anodize all the shrouds to match or maybe cerakote the whole gun/barrels but for now i'm just happy to be shooting this gun again.

 

[bannockburn]

bluejeans

Thanks for the update. Everything is looking pretty good so far. Like group #2 with the .38 Special +P!

 

[entropy]

Nice work! Should make a helluva woods gun.

 

[gotboostvr]

Very cool outcome.
Get it cerakoted OD green for optimal woods carry.
Just anything but hello kitty!

 

[bluejeans]

bluejeans

Thanks for the update. Everything is looking pretty good so far. Like group #2 with the .38 Special +P!

i think the gun will shoot even better than these groups show... i was kinda nervous/jumpy test firing this. i'm sure that is the cause of the fliers.

 

[gotboostvr]

Bluejeans, stopping setting the gun down, checking all the fittings, picking it up and picking back up a sight picture through those gutter sights isn't really conducive to accurate shooting.

A string of 8 without having to reaquire your grip or sight picture should be even better. I wouldn't sweat it.