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View Full Version : S&W K frame 327 mag.



leftiye
10-02-2008, 03:09 PM
Hi, I mentioned this project way back, and have been fiddling with it a little at a time ever since. It is a Model 10 (fixed sights) mated with an H&R 32 mag. 8 3/8" barrel with full under rib and cylinder for same caliber which I got from Numrich arms, plus a Millet rear adjustable sight.

Modifying it for the rear sight was the hardest part. You not only have to mill a groove down the top of the top strap, but you have to mill a T- slot at the rear for the S&W elevation t-slot nut. This t-slot is only about.040" thick and a special cutter had to be made from an endmill of appropriate diameter. Daunting at first, but once done, not so bad. The frame material on the Model 10 was free cutting (this was also a scary part, if you mess this up you start over with a new revolter), smooth cutting, and easy to mill.

Setting the barrel back to get a tight cylinder gap was somewhat tricky as the calculated cuts didn't produce the desired gap dimension, probly because of the cut suface "wearing in" when the barrel was installed. Took two tries because of this, and you have to make sucessive .001" or so cuts to bring the shoulder to where the barrel lines up (sights, and top flat) properly when tightened. I would because of this wait to cut off the barrel shank until after getting the shoulder right, and then follow the same procedure of small cuts to get the shank out of the way of the cylinder when it closes, and then obtain the desired cylinder/barrel gap (probly no extra cuts needed at this point if you want a small cylinder gap. A 5 degree forcing cone reamer was bought from Dave Manson and applied to the rear of the barrel after all else was completed.

As far as sheer work goes, fitting the cylinder would best be described as a nightmare. S&W factory cylinders have a LOT of extra metal on the rotating star, not so much on the rear, but on the lugs of the star where they bear against the hand when rotating. The correct surface to abrade must be identified (or you will ruin your extractor) and these filed, and finished with a diamond lap (not lapping compound, the abrasive hand tools), and just plain operating wear for the final fit. If you do it right, the result is no movement side to side is possible when the cylinder is locked up at the firing position. Chambers were lengthened slightly with a .339" reamer (factory chambers were over .100" too long for .32 H&R mag) to allow chambering the .327 mag. ctg. Chamber mouths were opened to .315" to match the barrel's .314" groove diameter. The headspace was brought down below minimum specs. ( case rims are still as much as .010" below minimum spec.), BEFORE fitting the barrel. Two .002" shims were installed to take out all feelable end play in the cylinder (also done before fitting the barrel - you should be able to see why). A .005" cylinder gap was obtained. I at first wanted a .002" gap, but decided it was too tight.

Of course a trigger job, and some touch up with Brownell's Oxpho Blue (I want to thank you guys for turning me on to this. It is the only cold blue I've ever seen to do a creditable job.) and now I'm having to keep it at arm's length to keep from slobbering all over it. I'm computer challenged, but I'll try to get my sexytary (wife) to help me get some pictures shortly. Now I have to get a reamer modified to open my 311316 Lyman mold to cast .315" diameter, as the barrel must have been a second as it has .314" groove diameter.

dubber123
10-02-2008, 06:34 PM
Cool!. Sounds like a neat, (if a bit in depth for me currently), project. Taking the pains to get the specs right should result in a great shooter.

Bass Ackward
10-02-2008, 07:55 PM
Sounds like a nice job that was almost fun. It will be VERY rewarding if it works out as planned.

How many degrees off did you use for tightening the barrel to avoid thread crushing a constriction in the barrel?

leftiye
10-02-2008, 10:29 PM
Dubber, Yup where I see the advantage of custom work is just that - getting the clearances and tolerances right, kind of "blueprinting" the gun. It is real frustrating how low the level of precision is in most guns, especially handguns. But then again those loose fits do help reliability, I guess.

Bass, I ended up with a slightly lose barrel fit, tight but not real tight. I would estimate maybe 45 degrees though from where hand tight stops to where the barrel is lined up. With those fine threads this is only about .004 to .005" of compression, or difference in position. There was a tight spot in the barrel when I slugged it anyway ( before I put it on my frame), but not too much. I think it will lap or fire lap out.

"IF it works out as planned" - ie. if it shoots straight. Yeah, I'm definitely anxious to find this out! It would be real disappointing if it all turned out so well, and then didn't shoot accurately.

crabo
10-02-2008, 11:06 PM
How about some pictures?

leftiye
10-04-2008, 07:08 PM
I got my SEXYTARY to take a picture! (do you believe that SWMBO wrote that? Well she did.)

Bass Ackward
10-04-2008, 07:18 PM
I figured that was pinned. That's why I asked what you selected for compression.

Looks good. Just a couple thousand jacketed and that ought to be ready for cast.

Cactus Farmer
10-04-2008, 09:26 PM
I WANT one too! When are the accuracy tests being done? Please post results ASAP.

2 dogs
10-04-2008, 10:43 PM
Well done!

9.3X62AL
10-05-2008, 02:39 AM
VERY NICE!

If S&W decides to bring out some revolvers in 327 Federal, I'll be hard-put to turn one down--especially a Kit Gun x 4". My current Model 16-4 x 6" is by some distance my favorite S&W revolver in the safe for plain old shooting fun, 'cause it's so bloomin' accurate.

leftiye
10-05-2008, 02:31 PM
Yep, It is a very nice gun overall, the barrel is heavy, but not too much so - not hard Atal to hold on a target, and steadiness is helped by the weight. The smaller caliber also provides lots of extra metal around the chambers. Not everyone's hand fits a Pachmayr gripper grip, but they were made for me.

As stated, accuracy will only be found out after I've reamed out my molds to cast .315" boolits, and worked up loads. And then maybe after some fire lapping if necessary.

Bret4207
10-08-2008, 09:05 AM
FWIW- Instead of using the K-Frame sight use the J-Frame adjustable sight. MUCH easier to install. Sweet gun BTW!

leftiye
11-09-2008, 05:20 AM
Well, I took the ugly beast (still no where near as ugly as an S&W X-frame! Actually, I think she's right purty!) out and shot a few shots today. American eagle 100 grain JSPs. With not having been sighted in the first shot rolled a gallon milk jug at 50 yards (one that someone left laying around on the range). I never did do any adjusting to the sights. After I took my glasses off so that I could focus on the sights I got a one onch group at twenty five yards. I guess I'm not much of a pistol shooter (but don't piss me off if you're within 200 yards), I'm guessing this thing is more accurate than I am. (Can't seem to get a woo woo to come up!)

James C. Snodgrass
11-09-2008, 06:10 AM
Sounds like you got it right the first time . I've never been lucky enough for sights to be on right out the gate . Great job on it hopefully S&W will offer some thing similar in the near future . James :mrgreen:

exile
11-09-2008, 01:19 PM
I just bought the SP-101 in .327 Federal, but have not shot it yet. Sounds like a great project. When you do some handloading for it, let us know. I will be very interested to hear your results.

Exile