Bye-Bye Bevel?

[Old Ironsights]

Could a Bevel Base be milled off into a GC base?

Say the 356637 but square it off just enough to take a GC so it can be driven to absurd speeds?

Doable?

[Willbird]

Are you talking of modifying an existing mold ??

If so you can sketch it up on graph paper and see, but unless it is a HUGE BB there will typically not be enough metal there to recut it into a gas check shank.

Bill

[badgeredd]

Could a Bevel Base be milled off into a GC base?

Say the 356637 but square it off just enough to take a GC so it can be driven to absurd speeds?

Doable?

I did something like that recently for my 375 SuperMag. I had planned on just shortening the cavity on a RCBS 37-250 mold to make a plainn base. Well I got to thinking and looking and got out a check and it looked like I would have enough height for the check if I bored out the bottom grease grove. Lo and behold it worked.

I'd guess that IF the bevel is high enough (meaning wide enough along the profile of the boolit) that one could do as you mention. I guess you can try it and if it doesn't work, just go for a plain base, right?

Edd

[Old Ironsights]

That's what I was wondering...

http://www.midwayusa.com/midwayusa/staticpages/highres/505491.jpg

[Willbird]

That sure is a honking big bevel base :-)

Bill

[JudgeBAC]

By the way, which mold is that?

[badgeredd]

Ironsights,
My Hornady GCs check @ .061 +/_ .001 on the inside depth. SO I would say if that huge bevel is .070 or more I'd sure try it. I know my check shank on the .375s is a smidge short compared to the shank on other molds but it is long enough for the checks to work fine...there just isn't much room above the crimped check. My custom mold produces a boolit (bare naked) that weighs in at 209 grains. PERFECT for my use.

Edd

[Old Ironsights]

Lyman 356637 125gr "Devastator"

Biggest prob is that it's only .356 and my guns like .358...

[Tom Myers]

Could a Bevel Base be milled off into a GC base?

Say the 356637 but square it off just enough to take a GC so it can be driven to absurd speeds?

Doable?

I made a blowup of the bullet image and scaled out the dimensions then entered the values into the Precision Bullet Drawing software and made a sketch of that.

Then I changed the bevel base to a gas check base and made a sketch of that one.

Next I overlayed the two sketches and it looks like you should be able to mill out the bevel base into a perfect gas check shank.

Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)


http://www.tmtpages.com/LinkSkyImages/forum_images/Composit%20BevelBase/Bevelbase.jpg

http://www.tmtpages.com/LinkSkyImages/forum_images/Composit%20BevelBase/Gas%20Check.jpg


http://www.tmtpages.com/LinkSkyImages/forum_images/Composit%20BevelBase/Overlay.jpg

http://www.tmtpages.com/LinkSkyImages/forum_images/Composit%20BevelBase/Bullet.Jpg

[No_1]

Another reason to buy your software Tom!

Robert

[Tom Myers]

Another reason to buy your software Tom!

Robert

Thanks Robert,

I am still working on getting some sort of a Bullet Drawing Software Version that will work for persons of average computer skills and will be able to install on all the different computer operating systems. The task has been immensely more than I had originally anticipated. But I'm still working on it.

Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)

[Old Ironsights]

All RIGHT... that's what I was looking for... Sweet.

Thanks Tom! (PM Coming)

[No_1]

Gentlemen,

To be totaly honest, When I viewed the picture of the mould I would have concluded that it would not work. I composed a post and was previewing it when I happened to look at again at what was already posted and saw Tom's post. Man was I ever wrong in my thoughts. Tom's software gave a no-guess answer to a question that most could only guess at. I am sold and will get it soon.

Robert

[Old Ironsights]

Frankly, looking at Tom's post and the Bullet Profile, I can't for the life of me understand why anyone would make a BB boolit.

A GC design serves the same purpose AND lets you push it if you want to. (That's how I use the 358156HP...)

And - again, looking at Tom's pic - you get an extra, if shallow, lube groove... ;)

[WHITETAIL]

Old Ironsights, Been there done that!
About a year ago I was thinking the same thing.
I like the results, and it now a favorite of mine.:castmine:

[oso]

I thought about doing just that with a taper reamer, but I get 4 already fine matched boolits out of my mold and wasn't sure 4 different cavities would be better - each cavity with its own thumbprint and 6 thumbs to spare!

[leftiye]

I'd vote for a straight chucking reamer. Use the same reamer on all cavities, you should get identical results. If lined up well, and controlled for depth (milling machine would be best) they should cut concentricly on the holes. I believe there's a table of gas check shank diametrs in Castpics or the stickies (or measure one on a .357 boolit). The extra, shallow grease groove supplies a place for the crap, and lead that the check scrapes off of the bore to stay until the boolit exits the bore. A good factor of gas checks for high velocity.

[dubber123]

Lyman 356637 125gr "Devastator"

Biggest prob is that it's only .356 and my guns like .358...

Try lapping it out. I just cast a pile of 358429's from a mould my brother got, and like a bonehead never measured them. Yep, just over .356". Crap. A little careful lapping got a nice even 358" boolit. Plus it drops VERY well now.

If they have never been lapped, just cleaning up the microscopic machining "fuzzies" in the cavities takes out the first .001" or 2 faster than you would think. Good luck.

[leftiye]

A little more complicated to fix. (casting diameter). You can modify a reamer (or make your own cutter), and make a holder to open up the bearing bands. Measure the mold across the bands at the parting line. This is tricky - you must measure at the very edges of the mold half. Add however much larger you want to get your boolits to be to the mold measurement, and purchase a chucking reamer that size. Modify the reamer By grinding the bevel off of the front end. leave the proper width cutter for your lands and cut down the flutes behind your bearing band section far enough to get into the mold to the front bearing band of the mold (don't cut any less off than will avoid touching any part of the mold or it will interfere resulting in oversize bands). A holder is needed that will keep the cut where you want it to be when opening up a given bearing band. I have a setup like this for .357, but it makes approx .360 boolits.

[Old Ironsights]

Try lapping it out. I just cast a pile of 358429's from a mould my brother got, and like a bonehead never measured them. Yep, just over .356". Crap. A little careful lapping got a nice even 358" boolit. Plus it drops VERY well now.

If they have never been lapped, just cleaning up the microscopic machining "fuzzies" in the cavities takes out the first .001" or 2 faster than you would think. Good luck.

Thanks... Cast one in somthing really hard then put some (what kind?) of compound on ti, then spin it in the mould with a drill?

Meh... I'm a Tanker Bar & 3# hammer guy. If I do this I'll send it to someone competent... [smilie=1: :mrgreen: