Unfired .44 Mag Brass Dimensions

[HPT]

I am looking for the reason I had a case separation today with my Puma .44 Mag.

I was wondering if the brass dimensions may be part of the problem? Where the case separated (which was .25" in front of the rim) the case diameter was .4605" wheras the case diameter just in front of the rim is .453" My thought is maybe my chamber is at the max SAAMI spec & my brass may be near the minimum?

I only have Winchester Brass to measure - so I was wondering if anyone has any unfired Brass of other makes that might have larger dimensions?

These are the dimensions I measured with my micrometer on new brass:

The average rim thickness of my new Winchester brass measures .053"

The outside diameter just ahead of the rim measures approx .4525"

The brass thickness I measure with calipers I get .012" to .013"


I am hoping there is a brand that uses larger & thicker brass ?

[JayinAZ]

I don't have any .44 magnum brass, but looking in Lyman 48th shows .457 just ahead of the rim.

[W.R.Buchanan]

Was that case new? or how many times fired? How many hot loads?

Strait walled cases seldom separate from minor dimensional discrepancies. Having the case expand .006-8 is not a big deal.

They do separate from being shot hard a few times, and in the case of .44 mag that can easily be done. What you describe is classic hot load case failure. The Winchester cases didn't help matters either. But I still use them for soft loads, and you can usually get 8-10 out of a case.

Starline makes the best brass as far as I'm concerned, and many will agree.

Try www.trackofthewolf.com for the best prices.

Randy

[HPT]

Was that case new? or how many times fired? How many hot loads?

Strait walled cases seldom separate from minor dimensional discrepancies. Having the case expand .006-8 is not a big deal.

They do separate from being shot hard a few times, and in the case of .44 mag that can easily be done. What you describe is classic hot load case failure. The Winchester cases didn't help matters either. But I still use them for soft loads, and you can usually get 8-10 out of a case.

Starline makes the best brass as far as I'm concerned, and many will agree.

Try www.trackofthewolf.com for the best prices.

Randy

Thanks for the response,

The brass was new. It had been loaded 2 times. The load was 22 gr IMR 4227 and a 240 gr XTP with the bullet seated so the brass aligns with the crimp groove. This has been the only load fired in this gun. There has been a total of 40 shots thru it. I fired the same load in my friends Marlin 1894 and the brass looks fine.

I put a few layers of masking tape on the back of an unfired brass and measured the thickness it took to get rid of all the headspace and it turns out to be .013" I don't know if this is excessive but I see that there is a tolerance of .010" allowed in the chamber & .011 allowed in the brass for a total of a possible .021". I know that my brass rim is .007" smaller than the max allowed of .060" so I was thinking that if I got brass at the max of .060" my headspace would be reduced to .006" which I think would be a lot better.

I can't seem to find anywhere what the dimensions of new brass is. You say that starline is best, could you measure the rim thickness & dia just in front of the rim?

[edler7]

SAAMI lists the diameter in front of the rim @ .4569
Rim thickness is .060

Here's the link to all specs. (http://www.saami.org/specifications_and_information/index.cfm) Go to SAAMI/ANSI Standards- ANSI/SAMMI Centerfire Rifle- download the PDF and 44 magnum rifle is on page 91.
It also lists measurements for headspace.

[HPT]

SAAMI lists the diameter in front of the rim @ .4569
Rim thickness is .060

Here's the link to all specs. (http://www.saami.org/specifications_and_information/index.cfm) Go to SAAMI/ANSI Standards- ANSI/SAMMI Centerfire Rifle- download the PDF and 44 magnum rifle is on page 91.
It also lists measurements for headspace.

Thanks Elder,

My Winchester brass dimensions are less than you posted, so I am trying to find if a different brand is closer. In the local sporting goods store both Remington & Winchester are available, but they are in closed bags - so I can't measure before I buy & starline has to be ordered in - again I won't know the dimensions until I get delivery of them.

I do have some starline brass in .38-55 and they are .003" closer to the specified diameter & I have some fired Federal .30- 30 & Winchester brass and again the Federal brass is .003" closer to the specified diameter.

Not knowing if Starline or Federal brass in .44 mag is also larger than winchester I was hoping someone having starline or federal brass could measure some. I think it would not matter if they have been shot - I'm just looking for the diameter just ahead of the rim & rim thickness

[edler7]

I found a new piece of Starline 44 mag in the shop. I'm 90+% sure it hasn't been resized.

Diameter just in front of the rim measured .45325 with a micrometer.
Rim thickness measured .056 with a set of calipers- couldn't get an accurate reading with a micrometer on it.

Hope this helps.

[TXGunNut]

Would be helpful to measure some fired brass as well. I'm also a big fan of Starline and the folks @ Buffalo Arms. Have had good luck w/ Remington brass as well.

[HPT]

I found a new piece of Starline 44 mag in the shop. I'm 90+% sure it hasn't been resized.

Diameter just in front of the rim measured .45325 with a micrometer.
Rim thickness measured .056 with a set of calipers- couldn't get an accurate reading with a micrometer on it.

Hope this helps.

Thanks Elder,

I will try some Starline. My first loads with the 240 XTP's were to try out the gun while I am waiting for a mold. I ordered a 2 cavity mold from Accurate Molds one hole is the 43-215 and the second hole is 43-265B that I designed to fit my gun.

I will order the Starline brass & hope it arrives around the time I get the mold.

[canyon-ghost]

http://www.starlinebrass.com/

I love starline brass. I've found Winchester to be a little harder than Starline, for some reason Winchester seems brittle. Never had one fail on the second or third firing though.


PS: Had a second thought, have you ever tried setting your sizing die about 3/8ths " high? I don't size the bottom part of the web, or get too close to it. No need to fatigue the case head.