I've been toying with bullets turned from SAE360. They shoot with expected speed and accuracy but will leave what looks like leading in the barrel, especially on the rifling lands.

It's a damn hard fouling to remove with cleaning solvents!

Any suggestions to reduce or eliminate this?

Solvents that eat brass fouling also desolve your brass jag and leave it in the same area you're trying to clean. Try a solvent with no ammonia or a plastic/delrin jag.

Check your bore/groove & bullet ID/OD's to make sure you're not squeezing the bullet more than necessary. Get a material cert. from your supplier so you know what you're actually shooting. All 360 are not equal.

Bullet design is also a factor especially the bearing surface area, and whether or not the bullet has driving bands/grooves to relieve the pressure on the bullet. Do you have any pictures of the bullets that you are using.

quote:

Originally posted by Macifej:
Solvents that eat brass fouling also desolve your brass jag and leave it in the same area you're trying to clean. Try a solvent with no ammonia or a plastic/delrin jag.

Check your bore/groove & bullet ID/OD's to make sure you're not squeezing the bullet more than necessary. Get a material cert. from your supplier so you know what you're actually shooting. All 360 are not equal.

No undue fouling in those 338 FN's you sold me, Mac

Thanks for the responses! Wasn't sure anyone would be interested.

The bullet in question is the center one (left is Barnes factory 500grain 458).



The major diameter is .620, minor diameter .600", nose is .612" diameter, first band is .300" wide, next four body bands are .200", and the base is .400".

The flats on our bands are .01" - significantly reduced bearing -vs- what you're currently using. Scope the barrel and see if it's rough. If you want to try some of ours to test for fouling get in touch with CCMDoc and see if he'll part with some. If not I may have a half box here.

Hi Mac,

The barrel is a PacNor from AHR and has about 150 rounds of assorted Woodleighs, lubegroove cast, paperpatch cast, and now these solids through it. It hasn't had any "break-in" treatments. Perhaps a few hundred more paperpatched slugs will ameliorate the fouling tendencies?

I can also turn more groove and less band on the next batch. How many bands does your bullet wear? What groove depth do you target? I assume anything reasonable smaller than bore is fine.

Do you think the choice of alloy has anything to do with it?

The Barnes bullet measures .457", as has all of the "458" solids I've purchased from them. They foul my .458Lott in a similar manner so I didn't think a slightly undersized major diameter would help. The Lott barrel is a .458WinMag rechamber and won't shoot cast bullets worth a hoot unless they're sized .460". As this is the second instance of this heavy fouling, and with a fitted slug, I thought I'd look into it a little further.

I'd talk to some of the other guys who've shot brass solids in the same rifle (600OK/Pac-Nor) & see what they say. Proper break-in in the begining might have helped - or may not. Polishing the bore with a rack of paper patched lead bullets may help - never tried it so no clue. C360 alloy is fine if that's what you're actually shooting. Get a material cert from your supplier to be sure. Most Barnes solids are undersized by a fat margin. You can ask them why they do that - I have my own idea.

Here's a look at our .620" x 800 Grain Brass FN. You could widen your grooves and keep the minor diameter at .600" - that should help somewhat. You must have a lot of extra time on your hands to be messing with making your own bullets...

your base band may be where the material is coming from.
i know with a cast bullet that has a long base band it will cause leading.

Not to hi-jack the thread. I do not know the SAE spec, but how would oil-lite work as a material for bullets? If not too hard I am inclined to think an oil impregnated material should be great!

Your Thoughts?

Andy b

Thanks for the spot on advice. Mac- I reduced the width of the bands, Lamar - especially the base band.

Fouling has been significantly reduced. More tests to follow but I don't think it's an issue anymore.

Accuracy remained at 3moa (PLENTY GOOD with 875grs@2450, iron sights & 200ft/lbs recoil energy!).

I did notice some "slippage" upon engraving with the reduced bands. Dunno if this will be a long term problem as these aren't for high volume shooting.

Version #1, Version #2, Version #2 recovered from backstop:

AndyB,

I played with some oil-impregnated bronze bearing material in my .458Lott. It definately is softer and had a tendency to deform more terminally than SAE360 but it too functioned well.

I didn't notice the softer alloy to yeild more or less fouling, pressure, velocity or accuracy but I did not do an extensive investigation. It certainly worked just fine in my brief tests however.

The design was more along the lines of Version #1 above so perhaps smaller drive bands would have made a noticable difference?