44 caliber gas check diameter

FourFortyFour
Posts: 3
Joined: Thu Nov 03, 2011 12:28 pm

44 caliber gas check diameter

Postby FourFortyFour » Thu Nov 03, 2011 12:45 pm

Hi Dan,

I'm not new to Mountain Molds but it's been several years since I've ordered from you.

My question is, it appears from your Online Bullet Design app that your default diameter for a .44 gas check shank is 0.400". Is it possible for you to cut my 2-groove 305 grain design with a .406" gas check shank? I will be sizing Hornady gas checks in a custom .433" die which should create a nominal gas check inside diameter of .401". The .406" gas check shank should provide enough grip so the check won't easily rotate on the shank.

Thank you,
FourFortyFour

User avatar
mtngun
Site Admin
Posts: 1624
Joined: Fri Feb 01, 2008 5:45 pm
Location: Where the Salmon joins the Snake

Re: 44 caliber gas check diameter

Postby mtngun » Thu Nov 03, 2011 4:03 pm

FourFortyFour wrote:create a nominal gas check inside diameter of .401". The .406" gas check shank should provide enough grip so the check won't easily rotate on the shank.

How do you propose to install a 0.401" ID check on a 0.406" OD shank ?

But that aside, your concern about the check rotating on the shank is misplaced.

FourFortyFour
Posts: 3
Joined: Thu Nov 03, 2011 12:28 pm

Re: 44 caliber gas check diameter

Postby FourFortyFour » Fri Nov 04, 2011 9:19 am

mtngun,

.401" would be the approximate inside diameter of an uninstalled gas check after running it through a .433" sizer. The check is spec'd to a inside diameter of .404" out of the box and I have a tool to flare the checks so they will slide over a .407" shank. Whether or not the check turns on the shank as it goes down the barrel is not the issue, (I assume this it what you mean by misplaced concern) it is simply quicker and easier to remove unwanted bullet lube form the base if the gas check is firmly in place.

Is it not possible to cut the shank a bit larger than .400"? A .400" shank on a .433" bullet would create a very loose fit.

444

User avatar
mtngun
Site Admin
Posts: 1624
Joined: Fri Feb 01, 2008 5:45 pm
Location: Where the Salmon joins the Snake

Re: 44 caliber gas check diameter

Postby mtngun » Fri Nov 04, 2011 10:07 am

With my stepped check shank, once the check is pushed onto the shank, considerable effort is required to remove it. This is BEFORE running it through the sizing die and crimping it on.

I understand your concern about handling loose-fitting checks at the reloading bench, but I've been sizing 44 checks to 0.432" for 25 years and never had a problem with a 0.400" shank -- even on a standard straight shank -- so I'm not understanding where you are coming from ?

Have you had a problem with checks falling off ? Whose mold ?

But to answer your question, no, I'm not going to offer custom shank diameters. If I did it for you, then I'd have to do it for everyone, and I don't want to go there.

FourFortyFour
Posts: 3
Joined: Thu Nov 03, 2011 12:28 pm

Re: 44 caliber gas check diameter

Postby FourFortyFour » Sat Nov 05, 2011 9:48 am

No, the checks don't simply fall off but they don't rotate with the bullet when wiping lube from the base. In other words, the gas checks stick to the towel when the bullet is rotated. Try it with a .433-.434" sized .44 that casts a .400" GC shank and let me know what happens. Perhaps it doesn't matter to you if there's a little bullet lube on your bases; however, living in the SW and shooting during the summer when 100F in the shade is a pleasant day, I'd rather not subject my powder to any possible contaminates.

Actually, the 2024 aluminum .44 mold I'm using frequently for my 444 had cast a .403" shank which I felt was undersized, so I carefully opened up the GC shanks with a nice sharp 13/32" twist drill and now the gas checks (even un-annealed checks) really hang on.

But to answer your question, no, I'm not going to offer custom shank diameters. If I did it for you, then I'd have to do it for everyone, and I don't want to go there.


That's fine, you can please some of the people all of the time, etc...

Thank you for your honest, unambiguous answer,
444

User avatar
mtngun
Site Admin
Posts: 1624
Joined: Fri Feb 01, 2008 5:45 pm
Location: Where the Salmon joins the Snake

Re: 44 caliber gas check diameter

Postby mtngun » Sun Nov 06, 2011 2:39 pm

I see, you are wiping off excess lube by spinning the bullet, and the check doesn't spin with the bullet.

When I wipe off excess lube, I slide the base across a paper towel. :roll:

I'm sure a fatter shank would grip tighter, the problem is, if it is too big, it becomes difficult to install the check without shaving lead or failing to seat squarely. A crooked check hurts accuracy, a slightly loose check does not.

A separate check-seating step can fix a crooked check, but it's an extra step, and on small bores and bore-riders, the force required to seat the check can unintentionally bump up the bullet nose.

When I make a mold for myself, I try to make the check fit on the loose side, for easy check installation, but when I make a mold for someone else, I aim for a tighter fit, because many people are worried about the check spinning on the shank, for reasons that have never been satisfactorily explained.

The check shank is subject to quite a bit of as-cast variation, so a perfect fit may be elusive. Again, I'd rather err on the side of easy installation, and as long as the checks don't fall off at the bench, I'm a happy guy. But that's just me. :lol:

A concave and/or hollow rod for the "I" die may help reduce lube buildup. Also a hard lube. I'm sure you already know all that, just throwing it out.

Good luck with your oversize shank.

User avatar
mtngun
Site Admin
Posts: 1624
Joined: Fri Feb 01, 2008 5:45 pm
Location: Where the Salmon joins the Snake

Re: 44 caliber gas check diameter

Postby mtngun » Sun Nov 06, 2011 3:01 pm

It occurred to me that my design program will, if you select the 446 caliber, allow you to create a 0.434" bullet with a shank for the 45 caliber check.

Even if the 45 caliber check spins on an unsized bullet, it should be plenty tight after sizing to 0.433".

This would of course require a better than average sizing die, with a generously tapered entrance. With a good die, it is effortless, but a bad die will mangle the bullet.

Long time readers here may recall that I once experimented with 30 caliber bullets cut for a 32 caliber check, just to rule out the spinning check theory. The oversize checks were squeezed plenty tight when sized down, but there was no measurable improvement in accuracy compared to a conventional 30 caliber setup.

User avatar
mtngun
Site Admin
Posts: 1624
Joined: Fri Feb 01, 2008 5:45 pm
Location: Where the Salmon joins the Snake

Re: 44 caliber gas check diameter

Postby mtngun » Fri Dec 02, 2011 12:41 pm

I happened to cut a 44 gas check mold today so I tested the check fit. Actual as-cast shank diameter on this particular mold was 0.4007" - 0.4011", a little on the fat side, but within spec. In practice, the customer will likely cast hotter than me, so I try to err on the fat side to compensate for heat shrink.

It took two hands to push the check on the shank. It did not shave lead, and it seated squarely if you pushed hard enough, but for my taste, it was too difficult to install. If I were loading these bullets, I would be inclined to use a check seater to save wear and tear on my thumb.

Once on the bullet, but still unsized, I was unable to spin the checks. Also, I was unable to pry the checks off using only my fingers.

This was plenty tight, regardless of sizing diameter.
Image


Return to “design & sizing”

Who is online

Users browsing this forum: No registered users and 3 guests