pushing cast 357 trough clyinder and barrel to measure

[magnumb]

I don't have pin gauges. I have never slugged my 357 revolvers (not really sure how).
I am using Missouri boolits that are generally .358 dia (some seem more like .359).
I am considering pressing one of these boolits thru my cylinder measuring before and after.

accourding to SAAMI the 357 cyinder is .3809 near base and .3801 at throat, thought maybe I could check by pressing a boolit thru.

Same idea for the barrel, could I press a boolit thru and measure before and after???

I don't want to get a boolit jammed in my barrel.

For the barrel I guess I would have to press thru from the muzzle end? If so should I put the boolit in backwards (nose first?).

All help appreciated.

Magnumb

[Hick]

I'll bet you get a lot of different answers-- but with mine I put the bullet nose first into the muzzle and carefully drive it through with a rod (It's OK to use a hammer to tap the rod, just be careful to keep it centered in the base of the bullet and don't let the rod touch the barrel, especially at the muzzle!!). Then, I tried sliding the resulting bullet through the cylinder throat. Conventional wisdom is that you want the cylinder throats to be slightly over groove diameter of the barrel. So, if a bullet driven through the barrel can be pushed through the cylinder throat by hand that's a reasonable indication that all is well.

[DougGuy]

Any alloyed boolit will have springback no matter if it's from running through a sizing die, a cylinder, or a barrel, the finished boolit will be larger because of springback. For measuring purposes, or using it as a comparator you would want dead soft lead since it does not have springback.

The measurements you are quoting is from SAAMI's chamber drawing, has little or nothing to do with throat diameters. S&W may be pretty close to groove diameter of the barrel, which btw has 5 lands and grooves so measuring this with a mic or caliper is error prone on the best day, even wrapping the slug in shim stock, measuring, and subtracting the thickness of the shim stock.

Ruger cylinder throats on the other hand are notoriously tight, often smaller than the groove of the barrel, and more often than not, inconsistent, all of the throats are not the same size. This is very common with Ruger revolvers.

You could push a dead soft lead ball through the barrel from the front, then see if it will go through the cylinder throats from the front of the cylinder. It should go with light finger pressure or very little pressure at all. If it won't go or has to be pushed through, that's a good indication that your throats are smaller in diameter than the barrel.

One other very common thing is your barrel may have choke where the threads screw into the frame. This is very common too, and will throw you off if you push a lead ball through a constricted barrel then find that it very easily goes through the cylinder throats, now you have inaccuracies on both sides of the matter, pushing a ball constricted by the thread choke in the barrel through the cylinder throats and think all is well when it really isn't.

What gun are we discussing here?

Here is a good way to check a barrel for thread choke without any precise method of measurement. Take a plastic cleaning jag and patch it tightly into the muzzle using one or two layers of paper towel so it's snug. Push it through the bore toward the cylinder, and note that any changes in resistance against you pushing the jag represents changes in the diameter of the barrel. If you get down where you are right at the barrel/frame junction and the jag gets tight? You are feeling the thread choke. If it's minor and you can barely notice it you may have a slight thread choke. If it doesn't change and goes on through the barrel and comes out? You have NO choke to worry about.

However if the jag stops hard and you have to force it through, you have a pretty severe thread choke, and pushing a lead ball through this choke and then testing it to see if it will go through the cylinder throats will NOT tell you if the throats are tight and need to be honed larger. It will only tell you that your swaged down lead ball will fit through the throats.

[243winxb]

I took unsized bullets. Loaded with light Bullseye powder load. (Less then starting load) . Filled 35 gal trash can with water & phone books. Stood on wall shooting down. Measure fired bullets. Size to same diameter or no larger the .001" Worked well for 357, 44 mag & 45acp. Standard diameters work well. .358" .430" & .452" if you can shoot the difference, try different diameters. The one 45 acp liked .451" best.

The 44 should be shot last. It put a hole in bottom of the metal trash can. :oops:

S&W needs a special way to measure groove diameters.

[mdi]

I have slugged cylinder throats of many of my revolvers. I used home made "slugging slugs" (soft alloy poured into an empty case and used an impact bullet remover when slug cools) and soft balls. Pretty accurate. I have used my unsized cast bullets and it worked, but I have a lot of soft lead and balls which are a bit easier When slugging barrels and/or cylinders I like a slug at least .010" larger than the groove diameter or throat. Do not use steel rods or wooden dowels for slugging. Steel can rub and ruin IDs and wood can splinter and jam in the barrel. Brass rods...

[bruce381]

yep thats what I do and the slugs u make in a old casing have a nice round edge to start easy

[murf205]

An oiled patch run through the barrel first will ease the pounding of the lead slug. I have a little plastic hammer I use to start the lead bullet because a steel hammer against the muzzle can be ruinous to the accuracy of that barrel. If you use a lead boolit start it nose first.
BTW, as far as the cylinder throats go, I just checked the Meyer Gage website and their individual pins are only $4.06 each. They are the easiest way to find out cylinder dimensions. I wouldn't be without them...my 2 cents.

[243winxb]

Why not tap a bullet part way into the muzzle? Not as far as this 9mm i did. On a revolver, pull bullet back out with pliers? If accuracy is not great or there is leading, then look for other issues. https://www.thehighroad.org/index.php?media/lee-356-120-tc-slugged-barrel-from-muzzle-end.3609/full