S&W 25-5 large chamber throats

[12 slugger]

Hi, looking for suggestions, my 25-5, 45 colt has 458 chamber mouths, 489 forcing cone enterance and 452 bore dia, any suggestions as to a heavy cast bullet, and diameter to size it, any help is appreciated, thanks

[runfiverun]

have you tried a 452 sized boolit?
even if you use a 330 gr gould boolit sized to 458 are you gonna be able to chamber it?
quite often just a good boolit with long bearing surface will make the jump and align with the bbl and shoot well.
i had to go try a button nosed wadcutter in my 41.
i was gonna have it converted to 44 special, till i tried that wadcutter.

[versifier]

Welcome to The Guide.

Just want to confirm a couple of things to make sure we're on the same page. I assume your .452 figure is groove diameter and not bore diameter. Big difference. Bore diameter is land-to-land, groove diameter is groove-to-groove (yeah, I know you have a 5groove S&W - measuring them does tend inspire creativity - many just measure throats & FC then try a few different bullet sizes progressively). FC measurement should be taken at the most forward part of it, by driving the slug from the back until it just starts to enter the barrel, then you pop it out and measure it. The only time there is cause for any concern is when the FC is smaller than groove diameter. Ideally it should be .001-.002 larger than GD.

Cast bullets should be sized between .001-.003 above GD. Some guns are more particular than others as to exact size they shoot most accurately with. Many pistols and some revolvers have chambers tight enough that they will refuse to feed the larger diameter bullets, so sometimes that limits the max diameter.

It's refreshing to hear that the throats and FC are properly sized. That is not always the case, even with the latest production revolvers. Sometimes the throat of each chamber in the cylinder are all different sizes (but a gunsmith can fix that pretty easily with a few minutes and the right reamer).

In .45cal, I generally only shoot the Lee230RN. It feeds in everything semiauto (mostly what I load them for) but it also shoots well in several .45LC revolvers I have tried it in. It should do fine in your 25-5. I have no first hand experience loading anything larger in the round, but I suggest you get yourself a copy of Lyman's Cast Bullet Handbook. It has all of the data you're looking for. I suspect others here with more experience with the LC can point you in the right direction.

[Paul B]

Hi, looking for suggestions, my 25-5, 45 colt has 458 chamber mouths, 489 forcing cone enterance and 452 bore dia, any suggestions as to a heavy cast bullet, and diameter to size it, any help is appreciated, thanks

I'm not doubting your word but if your throats are really that large, I would consider discussing this with Smith & Wesson. In my not very humble opinion, throats that measure .458 are way out of spec.
I just yesterday read an article in HANDLOAD #216 April 2002 by Brian Pierce on that very subject. (I keep a supply of reading material in the "throne room".) Apparently thee wee quite a few guns with that problem. Contact S&W and they'll tell you how to send it in for repair. That should be a freebie BTW even if some time has passed since the article. At the worst all it will cost you is the price of the phone call. At the best you'll have a gun fixed so that it will be accurate.
Paul B.

[versifier]

Just had a thought. Did you measure your slugs with a mic, or a caliper?

[12 slugger]

Thanks for the input, I am getting good accuracy at 25 yds with 451 sized 270 saa bullets but getting some leading, accuracy gos to pot at 50 yds, I am going to try a different bullet that drops from mold close to 457 and see how that works, also called S&W and they said send it in and they will replace cylinder for around 200.00, that will be my last resort