Plain Base Lyman 311679

[Ben]

I've wanted to experiment with a .30 cal. plain base mold.
Gas check prices continue to climb. I'm hoping to find a load that will shoot reasonably well without a gas check. Mild charges of Unique ( and the other fast burning powders ) with a plain based bullet may offer me what I'm looking for ? ?

This morning I thought I'd modify one cav.of a double cav. Lyman 311679 by removing the gas check shank. After removal of the gas check shank, the base of an " as cast " bullet is measuring .314. I cast several today and lube/sized them .3105 dia. The bullet, lubed and ready to shoot, is weighing 207 grs.

I realize that I will need to keep the velocities below 1,200 - 1,300 fps to achieve accuracy with this bullet. I shoot a lot of 50 yard .308 Win. and 30/06 with my cast bullets. Hopefully I can find a load with this bullet that will shoot well. I've always had good results from charges of Unique ...in the 06' around 11.5 grs. In the .308 Win., 10.5 grs. of Unique.

If you have load data suggestions for this plain based bullet with the 06' and .308 Win., please share your data with me.

Photos....................

http://img.photobucket.com/albums/v494/haysb/311679/PICT0004.jpg

http://img.photobucket.com/albums/v494/haysb/311679/PICT0025.jpg

http://img.photobucket.com/albums/v494/haysb/311679/PICT0011.jpg

http://img.photobucket.com/albums/v494/haysb/311679/PICT0006.jpg

http://img.photobucket.com/albums/v494/haysb/311679/PICT0026.jpg

http://img.photobucket.com/albums/v494/haysb/311679/PICT0027.jpg

http://img.photobucket.com/albums/v494/haysb/311679/PICT0002.jpg

http://img.photobucket.com/albums/v494/haysb/311679/PICT0003.jpg

dubber123 has requested that I share the procedure that I used to remove the gas check shank.

Here goes...........By the way...I don't claim to be a machinist ! ! !

I found in my box of drill bits, a super sharp .311 drill bit.
I set my mold block up in the drill press with the drill press bed
perfectly flat.
I checked the level in both directions ....Right - left and Fore and aft.
Once I have established that the drill bit is at a perfect 90 degree to the top surface of the mold I'm ready to drill. Next, I need to measure exactly how much I wanted the drill bit to enter the mold. Once that calculation was made, I adjusted the stop on the drill press for that dimension. Next I drill the hole. After the hole was drilled, I wrapped a piece of 320 paper around a wooden mandrel and spun the mandrel BY HAND in the hole a few times simply to clean up any burrs. I blued the area that was drilled with cold blue.

Photos below:

http://img.photobucket.com/albums/v494/haysb/Drill%20Press/PICT0006.jpg

Here I'm double checking the mold to be certain it is sitting at a true 90 to the drill bit:
http://img.photobucket.com/albums/v494/haysb/Drill%20Press/PICT0003.jpg

http://img.photobucket.com/albums/v494/haysb/Drill%20Press/PICT0004.jpg

Once I have satisfied myself that the bit is entering the hole PERFECTLY aligned, then I drill the gas check shank out of the mold :

http://img.photobucket.com/albums/v494/haysb/Drill%20Press/PICT0005.jpg

http://img.photobucket.com/albums/v494/haysb/Drill%20Press/PICT0002.jpg

UP-DATE ! !
I have a super accurate 311467 Lyman Double cav. mold. I thought while I was at it, I would take 1 cav. from it and remove the gas check shank also.....worked great ! !

Photos:

http://img.photobucket.com/albums/v494/haysb/PICT0008-6.jpg

http://img.photobucket.com/albums/v494/haysb/PICT0001-21.jpg

I've always cast from the front cav. of this mold, as you can see
from the photo below, it is super accurate with a gas check:

http://img.photobucket.com/albums/v494/haysb/88.jpg

http://img.photobucket.com/albums/v494/haysb/PICT0003-16.jpg

http://img.photobucket.com/albums/v494/haysb/PICT0006-5.jpg

http://img.photobucket.com/albums/v494/haysb/PICT0009-2.jpg

Here they are sized, lubed and ready to load:

http://img.photobucket.com/albums/v494/haysb/767.jpg

[Bret4207]

I was going to suggest 8-10 gr Unique to start with. Interesting idea. Let us know how it works.

[Ben]

I'll try to keep you posted.

[grumpy one]

Ben, I use 311255 (119 gr PB RN) in my 30-06 and so far it seems the maximum load of AP70N (Universal in the US) I can use is 9.5 gr, before the group opens up. However results are not especially consistent, and I'll have to do a lot more work before I'm confident. That load is with no filler of any kind.

By the way, so far it looks as if 6 - 8 grains of W231 gives slightly better groups, but I don't have enough data there either.

With your heavier bullet, or if you use a filler, I'd expect you'd want less of either powder than listed above.

[Ben]

Keep the info coming folks ! !

Thanks,
Ben

[dubber123]

I bet alot of guys would like to know how you removed the check shank. Is it a simple procedure, or is a milling machine involved?

[dubber123]

Ben, thanks for the additional pics. I got a bit excitable and did TWO of my moulds already. The plainbase flat nose for my 32-20 is the one I'm most interested in. I'll let you know how I did.

[Ben]

Give us an up-date !

Ben

[dubber123]

Well the 311291 single cavity came out well, the other one... well, it's a good thing it's a 2 cavity, it wasn't just right, so I decided to "fix" it. Oh, well, I'll take another stab at ruining the other cavity tomorrow! I'll be a little more careful next time. Done correctly, this does work well. The bit for 30 cal seems to be a 5/16". The one I had measured .312".

[JIMinPHX]

If you use a chamfer tool first, the drill bit will be more likely to stay concentric with the original hole. Just be sure not to send the chamfer tool in too deep or you will end up with the top of the hole being too big in diameter.

5/16 = .3125"...sounds about right for a .30 cal

[Bret4207]

You're a far braver man than I. My choice would have been a chucking reamer, but if it worked, good on you!

[JIMinPHX]

Chucking reamers do give much better finishes.

They can also be had in decimal sizes like .309, .3095, .310, etc for about $15-20 each.

The next size drill bit down from 5/16 is a "N" drill, which is .302".

The only problem with reamers is that they don't like to take more than about .005-.010" off at a time. It would be best to use a countersink or chamfering tool, then an N drill & then a decimal reamer in the exact size that you want. Unfortunately, most of us don't have a N drill or a chucking reamer in our drill indexes at home or our local hardware store, where as a 5/16" drill bit is about as common as toothpicks.

[Swamprat1052]

I'd like to try this with a Lee 300 gr 45 ca. mold. I always liked that mold but never wanted to fool with the gas check. Wouldnt be out near as much if I messed one of them up. Dont know what size bit I'd need but when I get it I could figure that out. The aluminum should make it easier to do.

Thanks for the good thread.

Swamprat

[Swamprat1052]

Looks like thats gonna be harder to do. I checked on drill sizes and cant find one I think would work. Anybody got any ideas?

Swamprat

[Ben]

I just looked at a drill bit chart, looks like it jumps from . 453 - .468 NOT GOOD !

Maybe someone that is a machinist here can offer some help.

Ben

[Diamond-City-Bob]

try a 29/64" bit, that worked for me on the Lee 310 grain. it's not quite right but it works in my Blackhawks

[Blackhawk Convertable]

Did the cast weight change much over what the GC's one's were weighing?