Sizing oval boolits- will it help?

[Beaverhunter2]

I've got a .480 Ruger SRH that slugs at .4755 (G-G) at muzzle, .4765 at the forcing cone, and .477 at the chamber(s). Now the problem, I have a Lee 400gr .476 mold that casts a boolit that is .4785 measured perpendicular to the mold lines and .4755 across the mold faces.

ACWW with LLA and a light load (8.5gr Unique) leads badly for about the first 3" to 3 1/2" of the 7 1/2" barrel. WC seems to do a little better with the same load. It seems like I have enough "diameter" to get the boolit to fill out the chambers and the cone. Will a sizer move the shape of the booilt or does it just "squeeze it down"? If so, what diamter sizer do you suggest based on my slugs? .477?

Or do you think my leading comes from something else?

Thanks for your help!

John

[leftiye]

Well, it should make 'em round. They (offset mold halves = boolits produced) actually are still balanced. Try 'em you'll like 'em! (maybe, that is). Also see if the locator pins can be set over in the right direction to make them round(er), then Beagle the mold to make boolits that are at least .477" in diameter. Then size them at least .477". The undersized boolits are part of your leading problem.

[Boomer Mikey]

Your boolits should be sized as large as possible but still chamber reliabily. If you can push them thru the cylinder throats easily your boolits are undersized.

A common issue with revolvers is the constriction where the barrel threads into the frame. Clean the bore real good and drive a pure lead slug all the way through the barrel to see what the real groove diameter is. Leading right after the forcing cone is common when pressures are low because the bullet has just been sized smaller by the constriction and then the hot gasses blow by the base gas cutting it.

Increasing your load may obturate your ACWW boolits enough to stop the leading.

If you're going to use mild loads:

1.) Try harder/and/or larger bullets as they are more elastic and will spring back more.

2.) Try softer boolits (add pure lead) to obturate easier.

3.) Go to a gas check design.

4.) Remove the constriction(s).

Adding some tin to your alloy may help them cast a little larger as well.


Boomer :Fire:

[jhalcott]

Beaver, I was thinking that YOU might be squeezing the mold a bit much and causing the off set. I KNOW LEE molds are not perfect, but then NEITHER am I.

[Bass Ackward]

Or do you think my leading comes from something else?

Thanks for your help?

John


John,

How many rounds you go through the gun? Look at the wear patten of the forcing cone? Are there any tool marks in the forcing cone acting like a file? You may need a few jacketed through there to get things more friendly.

IF this is a fairly new gun, hold the gun at an angle so that you can barely see the muzzle. This should give you minimal view of the rifling and grooves so that your eye can discern any variance easier. Rotate the gun around in a circle maintaining the same view. Helps if you have one of those little LED pen lights too. shining up from the forcing cone. See if the rifling - groove relationship all look the same to your eye. Or if there are differences. If there are differences, then something is happening back in the barrel that is deforming your slugs so that 100% contact with the bore is NOT made. After you lead, this will definitely be the case as the next slug will size to pass this point.

IF this is the case, then you will be victimized anytime that you want to shoot lead until it is corrected in some fashion.

It's quite possible that after you do everything right and that bore is worn smooth, that you may still lead. New guns generally improve right on up to about 10,000 rounds. Then what you have at that point is about what you can expect for the life of the gun. After it is all said and done, some guns will never be able to shoot a PB bullet so a Louis Lead Remover is a great tool to have.

Boomer gave you some things to think about if it isn't the gun.

[Boomer Mikey]

The trick to using cast boolits in revolvers is using enough pressure to obturate the base of the boolit but not enough pressure to exceed the strength of the alloy (too much pressure for the alloy used).

I don't believe your powder charge is producing enough pressure to obturate your ACWW boolit and if your boolits are smaller than the cylinder throats you won't be able to seal the throats enough to eliminate gas cutting.

Lead at the chamber end indicates a poor seal, lead at the muzzle indicates insufficient lube, or too much velocity for your alloy.

I recommend you start with boolits at least 0.001" larger than the chamber exit holes; ACWW alloy should be fine. Look up loads in the manuals to find the working pressure in PSI for those loads and use the BHN x 1422 formula to find the working pressure of your alloy... 1422 x BHN15 = 21,330 PSI this would be the pressure limit for a BHN 15 alloy (Lyman #2 or ACWW alloy). I'm reasonably certain that 8.5 grains of Unique doesn't come close to that. Unique is used to safely duplicate black powder pressures of 6,500 to 8,500 PSI used with BHN 4.5 - 6 pure lead boolits.

The following load data is for 400 grain Jword bullets but will be safe with cast boolits. I would recommend using a starting load powder charge and see if your leading problems continue.

400-GRAIN LOADS
POWDER PRIMER STARTING LOAD (grs.) VELOCITY (fps) MAXIMUM LOAD (grs.) VELOCITY (fps)
Winchester 296 Win. WLP 17.0 1,000 22.0 1,290
Hodgdon H110 Fed. 150 17.0 1,000 21.5 1,275
Hodgdon Li'l Gun CCI-330 15.0 1,000 19.0 1,260
RamShot Enforcer Rem. 2.5 15.0 950 19.5 1,265
Alliant 2400 Win. WLP 14.0 1,005 17.7 1,215
VihtaVuori N110 Fed. 150 15.0 950 17.8 1,160
Accurate No.9 CCI-300 15.0 900 18.2 1,210
All Loads feature Hornady's XTP-MAG Bullet

The 480 Ruger is a 48,000 PSI cartridge, although the 10 grain Unique load using the XTP 325 grain Jword bullet is popular; IMO 400 grain cast boolits would work better using H110, WW296, or Aliant 2400.

Read this excellent article about the 480 Ruger and loading it By Glen Fryxell, one of our esteem members here on castboolits.com: http://www.lasc.us/480Ruger.htm

Great job Glen,

Boomer :Fire:

[Beaverhunter2]

Wow! Thanks for all the info, guys! And thanks (again) to Glen! As I was reading the article, I realized I'd read it in the past. Good stuff!

My pistol is fairly new. Its had 500-600 shots through it. Mostly jacketed with some CP 425gr gas checks mixed in. This is one of the reasons I started looking into casting. I love to shoot, make my own stuff, and need to keep the cost down.

I water quenched some boolits yesteday and lubed 30 of them with LLA and 30 more with JPW. The JPW shot the best groups in my first tests. I'll push them a little harder than I did the others to see if that helps. I'll also do the same with some AC I made with the first bunch (lubed with LLA).

Put a U-joint in my truck this afternoon and have a steering knuckle to change out tomorrow. Hopefully it'll go smooth. If so, I'll have a chance to get back to the range. Wish me luck!

Thanks again, guys!

John