311299 W70 accuracy problem - are my boolits too small?

I just started using my new Lyman 311299 mold and am having some accuracy issues. Hopefully I can provide enough data to the forum so you can suggest what I may do to fix the problem. Are my boolits too small for this chamber as I suspect, or is something else going on?

I'm shooting .30-06 in my W70. The loads are over 16 grs of 2400 (I finally found some..) , OAL 3.245", which feels like it is just off the lands. With a 10 power scope I'm getting ~5 in. 10 shot groups at 50 yds. :mad:

I also loaded 10 rds over 32 grs of RE-15 to see if it did any better. The 10 shot group shrunk to 3-4", but I don't have much RE-15 left and don't plan on using it for this.

Shooting the same rounds, 16gr of 2400, in my M1903 with a receiver sight, I'm getting about 3 in. groups at 50 yds, which is about what I'd expect. My eyes are terrible, that's why I usually use a scope... Unfortunately, I don't have another .30-06 with a scope mounted to compare to the W70.



The details:

- My alloy is 50/50 COWW/Lino
- Lyman 311299 2 cav mold (200gr)
- I made the GCs with a Patmarlins Checkmaker using Amerimax .014 aluminum flashing.
- Lubed with my own stiff but gooey concoction of beeswax, carnauba, LLA, ATF, and synthetic 2-stroke.
- Sized with Lee .311 push through die.

I grabbed 2 finished boolits at random, took 10 measurements each

Boolit #1 min of 10: .3099
Boolit #1 max of 10: .3113
Boolit #1 avg of 10: .31053

Boolit #2 min of 10: .30915
Boolit #2 max of 10: .3114
Boolit #2 avg of 10: .31061

I did a pound cast of the W70 chamber and measured it 10 times.

PC min of 10: .3095
PC max of 10: .3096
PC avg of 10: .3094



Any suggestions would be appreciated, thanks.

I've found the 16 grains of 2400 to give good accuracy with any bullet in the 30-06 that fits well. The body diameter of your bullets seems to be OK. I have also found the nose diameter or the "bore ride" diameter to be very important. You don't mention the nose diameter of your bullets but for me a nose of .301" to .302" works well. This diameter should result in slight nose engraving in most rifles. If your nose diameter is .300" or under this could be the problem. I have several 30 caliber molds which drop with a nose diameter of .298" to .299" and they won't work nearly as well as bullets with a little larger nose.
Good Luck,
Rick

WhatRickinTN said, Chris! Btw, I too have a Win. Mod. 70, which is happiest with bore riding CB's whose noses are at least .301" and as large as .304". Accuracy is best when sized to .311", but .310" works almost as well IF the nose actually rides the bore.

I guess I'll go measure me some noses. BRB.

Quote:

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Originally Posted by Cmm_3940

I just started using my new Lyman 311299 mold and am having some accuracy issues. Hopefully I can provide enough data to the forum so you can suggest what I may do to fix the problem. Are my boolits too small for this chamber as I suspect, or is something else going on?

I'm shooting .30-06 in my W70. The loads are over 16 grs of 2400 (I finally found some..) , OAL 3.245", which feels like it is just off the lands. With a 10 power scope I'm getting ~5 in. 10 shot groups at 50 yds. :mad:

I also loaded 10 rds over 32 grs of RE-15 to see if it did any better. The 10 shot group shrunk to 3-4", but I don't have much RE-15 left and don't plan on using it for this.

Shooting the same rounds, 16gr of 2400, in my M1903 with a receiver sight, I'm getting about 3 in. groups at 50 yds, which is about what I'd expect. My eyes are terrible, that's why I usually use a scope... Unfortunately, I don't have another .30-06 with a scope mounted to compare to the W70.



The details:

- My alloy is 50/50 COWW/Lino
- Lyman 311299 2 cav mold (200gr)
- I made the GCs with a Patmarlins Checkmaker using Amerimax .014 aluminum flashing.
- Lubed with my own stiff but gooey concoction of beeswax, carnauba, LLA, ATF, and synthetic 2-stroke.
- Sized with Lee .311 push through die.

I grabbed 2 finished boolits at random, took 10 measurements each

Boolit #1 min of 10: .3099
Boolit #1 max of 10: .3113
Boolit #1 avg of 10: .31053

Boolit #2 min of 10: .30915
Boolit #2 max of 10: .3114
Boolit #2 avg of 10: .31061

I did a pound cast of the W70 chamber and measured it 10 times.

PC min of 10: .30845
PC max of 10: .30955
PC avg of 10: .30905



Any suggestions would be appreciated, thanks.

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Well the 311299 is a bore rider- which means the nose must ride the bore for accuracy. Since it's a modern 06, I imagine the groove diameter is going to be close to .308 and the bore will be close to .300. I also imagine the nose of the 311299 is NOT riding the bore. Measure the nose to find out or chamber a round, extract it and look for land marks on the nose.

If that's the case, here's my recommendation (bad news)- get a 314299, size to .309. You might even consider using regular copper checks.

Grabbed 10 boolits and measured noses about 1/3 of the way up from the front drive band, before the ogive starts.

Middle of the bell curve is .299" Range is +/- .0005" This is a brand new Lyman mold.

I inserted them into the crown of the muzzle and let them drop in up to the first drive band. I can jiggle them slightly. (Is this a valid test?)

Time to beagle?

Yes, a valid test unless your muzzle is wallowed out, which, if true, is also the cause of your accuracy problems!

Sounds like you found your problem. Trade the mold or buy a K31.

Yep, sounds like you found the problem, and not surprising on a Lyman mold. You could either lap the nose to .301" or so or order a mold from Tom at Accurate molds of your choosing. I order noses of .302" from Tom for my 30-06's. His tolerance on noses is +0.000"/-0.002" and I usually end up with noses of about .3015" or so with my alloys.
Rick

Quote:

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Originally Posted by Cmm_3940

Grabbed 10 boolits and measured noses about 1/3 of the way up from the front drive band, before the ogive starts.

Middle of the bell curve is .299" Range is +/- .0005" This is a brand new Lyman mold.

I inserted them into the crown of the muzzle and let them drop in up to the first drive band. I can jiggle them slightly. (Is this a valid test?)

Time to beagle?

---

That's no surprise with the current crop of Lyman molds. An older #314299 or #311487 (Loverin design) may improve things, but they're relatively rare and pricey. Beagling what you've got is so much easier and way less expensive. If that doesn't improve things, you can at least clean and sell off #311299. And, yes it is a valid test.

It looks like I have something (else) to do on the next good weather day. Thanks, everyone!

You could also try more linotype to increase the nose diameter.

That, and try casting with a little cooler alloy temperature.

You don't say how long you wait after casting to shoot. I like to wait 3 weeks for air cooled boolits and 5 days for HT'd boolits. I believe diameters will increase a hair also.

Powder coating would be another option.

Alloy temp was 725° on the PID. Around 700° I start to have problems with fillout and the spout on my bottom pour freezing.

boolits were water dropped, a week or so before sizing, and a couple months before loading/shooting.

You mention in your first post that 32gr RL15 increased accuracy a bit. Probably by obturating the boolit a little more. Do you have a powder that would boot that boolit a bit faster, it seems to like it. Air cooled boolits might obturate better using the 2400.

I've read that wrapping the spout with a piece of welders blanket will help insulate it to prevent it from freezing.

I have a couple of molds for long bullets like a 200 gr SP. That will cast larger if I use the pressure pour method with a hand held ladle with spout.

you can walk the 2400 load up some too.
I'd fix the nose until it shows engraving from the lands when the round is chambered.
either by changing the alloy, or through lapping [siiigh]

two of my 0-6's like 19 grs of 2400, one likes the 311041 and the other the rcbs 30-150.
the one thing the two boolits have in common is that the nose engraves evenly all the way around in both rifles.
it's probably why they shoot so well too.

my 314299 is too big to use in the 30 cal rifles, it has a 304 diameter nose.

My 311299 was to small so I sold it. .310 diameter, .298 nose.
I went with the 314299. .3125 diameter, .302 nose.

Shiloh

I have a question
Have you cleaned the copper out of the bore?
If no, give the bore a good cleaning with copper solvent
Then shoot it with cast and give us a report
Mike

Here's a pic of my 314299 nose. I ladle pour, use an alloy of 12-14 BHN, fairly soft lube and sized to .309 or .310 depending on rifle. Seems to work very well for several 06s.

I don't know if it's this mold or related to the alloy. But the noses are very consistent at .302.

+ 1 on Linotype, more tin antimony will increase the size.
Also NOE sells a 312299 with a 301 nose.

Just to pile on.. Getting the bore ride section up to a snug fit may cure your problems. I have a Savage 219 in 30-30 that shot around 2-2 1/2" at 50 yds. with the 311291. My Lyman had a .300" nose. I lucked into a LEE GB mold that cast at .302"+ on the nose. Same loads, in the .4" range at 50 yds. Amazing difference.