357 Max and PC cast

[Lost Oki]

Have a H&R rebored to 357 Max. and am trying to shoot 180gr cast PC bulletsat .358 using Lil Gun.  at 19 gr. I get a 2.5" group at 20gr it opens up to 5" at 50 yrds off rest.  Am I trying to push the Polymer coated bullets to fast ?     Note: Barrel slugs at about .357 and chamber is tight an will not take a .359 dia bullet.

[orerancher]

If the Powder Coating was done Right I don't think that's The Problem...
Try a different Bullet..My Contender Max Barrel likes the Lee 358-200.
And Definitely try other Powders!! 

[jedman]

In reading your problems of using a 358 bullet and a .359 will not chamber that is too tight ! If you have less than 001 clearance for the fired case to expand and release the bullet that alone can create many problems.
I have never heard of anyone neck turning straight walled pistol brass before so maybe you could use a 357 max casing drill and tap where the primer pocket is and thread in a bolt or machine screw without a head to use to spin the case with a drill motor.
Load the empty brass with a 9 mm or .357 bullet to keep the case mouth supported and with valve grinding compound and the bore plugged you should be able to polish the chamber to slightly ( .001- .0015 ) larger so it will chamber a .359 bullet with sufficient clearance and try using heavy for caliber bullet PC coated.
I have 3 rifles chambered in 357 maximum and one thing I have found in all of them is if your not after top velocities a slow powder like R 7 shoots MOA with cast in all of mine . It’s a good powder because you probably can’t get enough of it in a max case to be over pressure and with heavy bullets you will get all of the velocity you can reasonably get with a non gas checked PC coated bullet.

Shooting jacketed bullets is a different thing altogether, with the 357 max most find a 180 gr with AA 1680 to be a great combination.
You may not need to do anything I mentioned if you can find a .357 bullet and powder your rifle likes but if your handi is set up right you should be under a inch at 50 yards easily.

Jedman

[cwlongshot]

Have you played with seating depth? I have a half a dozen thrifty seven max firearms and they're definitely not all created equal. One original H&R maxi it's very deep throated and will take even my 270 grain or 280 grain lyman boolits. But I savage 24 is very tight throated and requires deeply seeded bullets. Bullet manufactures specifically cast do not or did not design bullets for powder coating. So when we powder coat traditional bullet designs you get a very fat bullet through the ogive that severely changes how they have to be seated.  CW

[orerancher]

Have you played with seating depth? I have a half a dozen thrifty seven max firearms and they're definitely not all created equal. One original H&R maxi it's very deep throated and will take even my 270 grain or 280 grain lyman boolits. But I savage 24 is very tight throated and requires deeply seeded bullets. Bullet manufactures specifically cast do not or did not design bullets for powder coating. So when we powder coat traditional bullet designs you get a very fat bullet through the ogive that severely changes how they have to be seated.  CW

NOE has a few Designs with no Lube groves...Just for Powder Coating....

[cwlongshot]

Im aware, but the ojive is unchanged. The designs of these bullets are just minus grease grooves not made undersize to allow for the .002-.004 powder coating increases.

CW

[orerancher]

Im aware, but the ojive is unchanged. The designs of these bullets are just minus grease grooves not made undersize to allow for the .002-.004 powder coating increases.

CW

A Push thorough Sizing Die will Handle That...

[cwlongshot]

No actually it will not, the ojive of the bullet is not sized thru a bullet sizer.   You CAN just nose size, but its not a viable choice to change this.

[orerancher]

No actually it will not, the ojive of the bullet is not sized thru a bullet sizer.   You CAN just nose size, but its not a viable choice to change this.

Maybe You need a Different Bullet.....

[cwlongshot]

Im not having issues, I am responding hoping to answer questions posted by LOST OKI.

[Lloyd Smale]

pc is great but it doesnt eliminate the fact that harder bullets about always outshoot soft ones.. To soft and you can strip through the rifling and if the bullet doesnt engage the rifling correctly it wont spin as fast and it would explain why your groups are opening up. IMO for what its worth you should be casting with an aloy of at least 15bhn and better if its 18 or even harder. Also at those velocity's a gas check bullet design will about always out shoot a plain base even when pc coated. First thing i would do is shoot some into some milk jugs full of water so that you can recover a bullet and see what it looks like. See if it has clean rifling marks and if your pc is actually staying on the bullet. I dont know crap about the 357max but id also look at what twist your barrel is and if its the standard twist for a 357 max or a slower twist for lighter 357 mag bullets.