Marlin Firearms Forum banner

older .458 bullets

177 Views 4 Replies 3 Participants Last post by  HIKayaker
I have a quantity of each of these bullets but I know very little about them. Diameter is .458 and weight is 300 gr. so I assume .45-70.
Not cast for a gas check? Is that important?
What is the middle one coated with and how does it compare to plain lead?
The lubricant appears to be wearing out of the third bullet, is that critical?
How are these in a micro-groove barrel?
Thanks for any help.

See less See more
1 - 2 of 5 Posts
I would measure each of the different kinds of bullets for diameter. Use a micrometer or a digital vernier caliper. The boxes or bags might say 0.458" but they may be larger--which would probably be a good thing.

Slug your barrel. Directions are easily found in MO and on the web. Usually best performance with cast bullets is obtained with bullets 0.002-0.003" larger than groove diameter. My Marlin 1895 wants its cast bullets to be 0.4595" or larger fore the accuracy I expect. However, your rifle may not be as picky. You will need to try your rifle for yourself. Load some up and shoot them. This is for Microgroove rifling. I don't know how things are different for Ballard rifling. Various shooters have their own (sometimes very strongly held) preferences for one or the other. Microgroove rifling was begun by Marlin in 1953 as a cost saving measure, as it is faster and cheaper than installing cut rifling. One is neither particularly more nor less accurate than the other.

The gray bullets are both lubed lead. The middle one is copper plated--or maybe copper washed. The copper doesn't add anything to hardness, lubrication, or accuracy. It is essentially cosmetic. Copper plated lead bullets are available today from various manufacturers, but max recommended velocities are still in the 1600-1700 fps range.

All three bullets should still be lubed from production/casting. You will probably be able to feel the tackiness of the lube still on the bullets. It means almost nothing that some of the lube has fallen out of the grooves. There will be enough on the rest of the bullet(s) to function through the barrel. I believe that after a few rounds, the bore of the barrel gets coated by lube and this serves to function for the bullets that may not be completely coated. Further bullets replace the coating in the barrel. At least that's the way it is with 22LR which also shoots lubed lead bullets. Of course the cast bullets are not pure lead and they are harder than than 22LR bullets. You may see better groups if you run 3-5 bullets through the barrel before you start shooting for accuracy. Same for switching kinds of lube on different bullets.

Common wisdom suggests that lubed, cast bullets can be driven to 1600-1700 fps before leading becomes a problem. Some folks are able to drive them faster with out problems. If you want 1800fp and higher, you should look into gas check bullets. Gas check bullets usually have a recess molded at their base to accommodate the check. But with an appropriate press, gas checks can be squeezed into the base. This causes a mite of distortion to the base, but typically doesn't affect accuracy. Accuracy with gas check bullets has a lot to do with how uniformly square the check is applied to the bullet base.

Leading at higher velocities seems to be from propellant gases escaping around the base of the bullet. The leaking gas carries some vaporized lead which then attaches itself further up the barrel. The gas "checks" or stops this escaping gas and allows the bullets to be driven faster. Lead and cast alloy bullets will seal the barrel only up to a certain pressure before gas leaks past the base of the bullet. The increased pressures needed to drive the bullets faster eventually reach a lever where the lead/cast bullet is no longer sufficient to seal the barrel. The bullets will still shoot, but they will lead the bore and accuracy may decrease.

Hope this helps.
See less See more
  • Like
Reactions: 3
If those bullets mic 0.461" I'd say load them up and you're good to go.

It's your choice as to velocity. If you load them to about 1200 fps they will have very little recoil. For that level, I would suggest Unique or Trail Boss powders. Or load them a bit faster 1500-1600 fps. They will recoil like a high brass 12g. At that velocity you will have many possible powder choices.

Good luck. Enjoy.
  • Like
Reactions: 2
1 - 2 of 5 Posts