147gr M80 FMJBT Load Data Different OAL?

[805hitman]

Ok with my normal 147gr M80 load, I use the bullets on the left, they vary in a OAL of 1.535"-1.1635". I use 17.1gr of H110 with a OAL of 2.140 & get great results.
With my new batch of 147gr M80's that I got the OAL of the bullet varies between1.0845"-1.0970". My question is, what should my OAL be? Shorter around 2.07 if I want to use the same charge of 17.1grs of H110?

Thanks!

[20X11]

Not that simple...with that much difference in projectiles, you SHOULD rework the load from the beginning.

[805hitman]

Not that simple...with that much difference in projectiles, you SHOULD rework the load from the beginning.

Even though the bullet seating depth should be about the same? What do you think is a good starting point?

[20X11]

Not that simple...with that much difference in projectiles, you SHOULD rework the load from the beginning.

Even though the bullet seating depth should be about the same? What do you think is a good starting point?

Yes, even though the seating depth should be about the same, the bullet "bearing surface" may be different...it is enough of a geometry change to potentially affect pressure and accuracy.

If it where me, I'd back off a full grain and re work a load ladder in .2 gr increments testing for accuracy, velocity(chronograph), and pressure signs.

[Bretzky]

Hello.

This is my first post, and I pick a topic that hasn't been touched in over a year, so forgive me for not starting a new thread.

I've been reloading for probably 30 years or so, and I've never had this problem before, but I see I'm not alone. I purchased 3,000 147gr M80 projectiles a long time ago with the idea that I'd use them in my M1 Garand, but like so often happens, I never got around to loading them up. Fast forward several years, I'm excited about the 300 blackout, and I decide to try these bullets. I prep my cases, trim them all to the same length and begin loading with a taper crimp. The first round is beautiful, as it should be because I used it to get the die just right. Run the second case up and crunch the case. I'm confused. I load several more and they're seating all over the place, some are in the cannelure like I want them, some are too deep, some not deep enough and I'm at a loss. Finally, I start measuring the bullets, and I'm seeing the same thing the OP is seeing, the bullet lengths are all over the place. I tried measuring them from the ogive, and that's all over the place too. I'm at a loss as to how to load them consistently. Should I just toss them? I'd be interested in any ideas you may have.

Just so we're clear, I'm loading these using RCBS Small Base Taper Crimp 300 Blackout dies. Cases are newly formed from 223, so they're all at minimum length, all full length resized, the cases are not the issue.

Thanks!

[cdl]

I went through this too. There are good batches and bad batches...

My first suggestion is to seat and crimp in two different steps.
Then try a Lee Factory Crimp, they're like $14.00 and more forgiving.

Then, if the groups are wild, when you get time, using a comparator, sort the bullets and measure ogive to base. This seems to work better than by weight or OAL on these wild ones.

[dellet]

Hello.

This is my first post, and I pick a topic that hasn't been touched in over a year, so forgive me for not starting a new thread.

I've been reloading for probably 30 years or so, and I've never had this problem before, but I see I'm not alone. I purchased 3,000 147gr M80 projectiles a long time ago with the idea that I'd use them in my M1 Garand, but like so often happens, I never got around to loading them up. Fast forward several years, I'm excited about the 300 blackout, and I decide to try these bullets. I prep my cases, trim them all to the same length and begin loading with a taper crimp. The first round is beautiful, as it should be because I used it to get the die just right. Run the second case up and crunch the case. I'm confused. I load several more and they're seating all over the place, some are in the cannelure like I want them, some are too deep, some not deep enough and I'm at a loss. Finally, I start measuring the bullets, and I'm seeing the same thing the OP is seeing, the bullet lengths are all over the place. I tried measuring them from the ogive, and that's all over the place too. I'm at a loss as to how to load them consistently. Should I just toss them? I'd be interested in any ideas you may have.

Just so we're clear, I'm loading these using RCBS Small Base Taper Crimp 300 Blackout dies. Cases are newly formed from 223, so they're all at minimum length, all full length resized, the cases are not the issue.

Thanks!

Surplus bullets suck in general, but they can be pretty good if you sort them. Most important is base to ogive. That should get you a consistent seating depth and jump. COL is another story, but if you sort by length after base to ogive it will get better. Then if you want reasonable groups you might sort again by bearing stupefaction length and or boat tail. If you look at the original photo, you can see the difference in tail length, that will screw with your case fill ration.

You will need a comparator to sort the bulletsmif you don’t have one.

As for crushing the case, first thought is mixed headstamp or improper die setting.

If you used the same cartridge to set your crimp by seating, screwing the die down a bit more and trying again, you slowly, step by step reduced the neck size. Then put in a new case and it was too much in one step.

With mixed headstamps, even if they are trimmed the same length, the thickness can be different causing the die to contact sooner or later in the taper of the die.

Hope that might help some.

[Bretzky]

Hey Dellet,

Thanks for the reply. I did begin sorting them, but I'm going by length first, figuring that my seater isn't making it all the way to the ogive anyway. I do have a comparator though, and I'll at least measure base to ogive within groups. I just cannot believe the variation I'm seeing, and I'm almost wondering if it's even worth it (or safe) to attempt to use them. I'm seeing lengths from 1.085" to 1.152" which just blows my mind. Bullet weight on the other hand is very consistent, within a grain or two. It's no wonder I had so much trouble when I first started shooting DCM matches with my M1-Garand and military ammo! I like to think that in the same lot you won't see as much variation, but when I switched to match bullets, the difference was night and day. I figure these will be okay for cheap plinking ammo, but we'll see. I'm probably going to have to be "happy" with 4"-5" groups at 100 yards.

[dellet]

Hey Dellet,

Thanks for the reply. I did begin sorting them, but I'm going by length first, figuring that my seater isn't making it all the way to the ogive anyway. I do have a comparator though, and I'll at least measure base to ogive within groups. I just cannot believe the variation I'm seeing, and I'm almost wondering if it's even worth it (or safe) to attempt to use them. I'm seeing lengths from 1.085" to 1.152" which just blows my mind. Bullet weight on the other hand is very consistent, within a grain or two. It's no wonder I had so much trouble when I first started shooting DCM matches with my M1-Garand and military ammo! I like to think that in the same lot you won't see as much variation, but when I switched to match bullets, the difference was night and day. I figure these will be okay for cheap plinking ammo, but we'll see. I'm probably going to have to be "happy" with 4"-5" groups at 100 yards.

Not necessarily
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