tight smith

[bigted]

smith & wesson model 629. 4 inch barrel. the bore is .4235 and the groove dia is .428. the cylinders all meassure at .429 at the mouth.... no big differences there.

what prompted me to do this meassurment is that im having a leading problem with all boolits i try. the group also strings vertical every time.

the powder used is 2400 and unique. loaded around 900 to 1000 fps.

ive tryed so far a lyman type 300gr sized to .430 .

the next boolit tryed is some cast boolits ive had around since the begining of time or so...they are 240gr sized at .4315 and i dont even remember where i got em from.

the next boolits are bullets and they are hornaday j's 240gr xtp's and they meassure in at .430 inch as well. i havnt shot any of these as i wanted to remove all lead before i try them. i got all the lead out but then i decided to meassure the bore n groove as well as the cylinder mouths before going further.

is this a tight gun or is it just me? seems like with the .429 cylinders that i need to keep the size of my boolits at this meassurement. but what about the jacketed that meassure in at .430... wont they develop more then their share of preassure and consequently accuracy would go south.

so what say yee...is she a tight one or just about rite? is the tight bore n groove the reasson i cant get any accuracy and all this leading?...:coffeecom...[smilie=1:

[MtGun44]

The dimensions you quote are excellent, not part of your problems with boolites or
any issue with bullets.

What lube are you using? Try a Keith or LBT design with NRA formula 50-50 lube. These
are known good designs and lube, should work at .430 with your dimensions. Try
8-10 gr Unique. After you do this, please report back.

Again - do not think that this is your dimensions, they are a touch tight but excellent
in that the throats are +,001 on the groove. This is perfect. With a .429 or .430 lead
boolit, you should have good accy and no leading. Perfect for the .430 XTPs, too.

Vertical stringing is either inconsistent ignition or inconsistent grip or rest. Are you resting
the butt on a bench? This can definitely do that. Test from a sitting position with back
rested and wrists between knees, or from a bench with the grip well clear of the bench
and the front edge of the frame against a sandbag, preferably protected with a piece
of sacrificial cardboard or leather.

Bill

[runfiverun]

is the leading at the end of the bbl?
or does it start at the bbl right after the frame.
i'm thinking you got a tight spot in the bbl.

[bigted]

its rite at the begining of the barrel and streaks down the bore. maybe i do have a tight spot where the barrel screws into the frame. i cant feel it with a tight patch tho.

the lube is what came on these 240gr boolits...ive had em for years and dont remember where i even got em...i didnt cast em nor lube em...they would group into one hole with my old '29' tho at this 25 yds distance.

i bought several box's of 300gr .430 inch boolits from a local feller and ill have to shoot them again to be sure that they left lead as did the 240gr'ers. i loaded up some hurtin loads to carry with me in the bear fields.

i have a lyman 300gr boolit mould and i plan to cast some of these and will lube em with nasa lube from bull shop's as i plan to use bp in her as soon as i get these first cast boolits lubed...only prob is that all i have for a sizer now is a .431 inch size die. got a .430 and a .429 on the way tho.

i meassured the cases im useing as well and they did come in all over the map for length. ill length trim em before i try any more...this could be exactly where the verticle is coming from...i dont allow the gun to touch anything but my hand when i shoot and i use the same hold that ive always had so good luck with. i will pay attention to this tho as im almost back to scratch with my pistol shooting it seems...very discouraging as i used to be an exelent pistol shot...won several dollors back when with shooting others guns and showing them what their guns were capable of......getting old is the pits i tell ya...golden years my ass...lol

[Bass Ackward]

smith & wesson model 629. 4 inch barrel. the bore is .4235 and the groove dia is .428. the cylinders all meassure at .429 at the mouth.... no big differences there.

[smilie=1:


Really? Is this angled rifling or the more conventional broached? Cause your rifling height is just a shade over .002 if this is correct.

If that IS correct, and you have the angled rifling, good luck.

If you have conventional, then you are probably going to be .... velocity challenged and number of rounds between cleaning limited. (severely limited)

My guess is that your bullets will be easier to turn over by that low rifling and over come the friction in the throats with a smaller diameter bullet. OR another way of saying this is that the smaller diameter will have a higher velocity potential.

Proof of the taste though is in the puddin.

[44man]

Bass is right, rifling that shallow will cause all kinds of problems with cast.
I question measurements with 5 grooves and lands too.

[MGySgt]

5 Groove - ug

Some one was selling a tool to help measure a 5 groove - don't remember who.

For my Smiths - I slug the barrel and see if it will slide through the chambers with little to no force.

I then slug the cylinder and size to it or slighly larger.

[msinc]

I have two S&W's with tight dimensions similar to yours. One is a new 629 and the other is a new 686+DLX and just like you I had the leading problem. I couldn't get 50 rounds out of either gun without having to stop and clean/de-lead. Tried sizing the bullets smaller...larger...dead on, tried different powders and loads...gas checked bullets, J-B Bore Bright, different alloys...but they always leaded. Then I read about a Taylor Throat, looked for the reamers but nobody listed or carried them anymore. So I called Manson Precision and he made me the reamers and an 11 degree forcing cone reamer. So far absolutely no lead in the barrels. I've only had time to shoot them a few times but, zero lead...I have a borescope.

[bigted]

well yes i do have a 5 groove smith and it somehow missed my eyes when i fooled with the bore slug...upon further inspection they are 5 groove and how i missed this is beyond me.

msinc...thanks for the suggestion of the 11 degree cone. ill digest this and search for one and see if this does the trick. i notice that the existing cone is rough and ribbed [ machining marks] so next ill try to smooth this out and see if this does anything for my lead mining problem.

i will need to make this a cast shooter as the practice is invaluable when the furred and growling get in your face here i need to be able to instinct shoot without hesitation of wondering where the dang boolits are going to go. human antagonists are dealt with in other ways but the large hungry bears here dont savvy understanding and threats...they are just hungry and pissed all the time.

thanks all and keep em coming...all valuable info

[msinc]

It probably already has an 11 degree cone but you are seeing what shamefully many owners of S&W revolvers see these days...poor QC. Both my guns had very rough chattered forcing cones. Others brought into the shop are typically so bad that they are too chattered to get all of the gunch marks out. You must be careful not to enlarge the FC too far. There is an optimum size and if exceeded the accuracy will suffer. I cut them enough to level out some of the bad marks and not exceed the FC gauge.
Taylor throats are a little misunderstood. They were developed to stop leading in sillouette pistols so they could get through a match without having to stop and delead the gun. I have found as have others that it works very well for that. It will also help accuracy in a revolver that has timing issues where the cylinders are inconsistent to line up with the barrel. Many shooters relate the Taylor throat to accuracy improvement. However,a Taylor throat does nothing for accuracy in a revolver that is properly timed. It has the added benefit of a small increase in velocity.
You probably also have the new style rifling that is actually cut with an EDM machine. It works good once you break it in but if you look at it with a borescope the entire inside of the bore appears to have been sandblasted. I always lap the bore in one of these with JB Bore Bright. If after a few hundred rounds you still have leading issues {dont be too surprised if you do} I would seriously consider the Taylor throat and forcing cone clean up. Good luck.