450 Bushmaster case head expansion question

[KG4EIQ]

I reloaded my first 450B rounds today, I chose to start cautiously and work up as I've learned to do with other calibers. I loaded new Starline cases with 35.0grs. of Lil'gun, 250Gr. Hornady FTX bullets, lit by CCI 400 primers I used a Lee factory crimp die set to .477", my C.O.L was 2.225". Everything went fine, all the rounds chambered, fed, and ejected at 3 O'clock 6' away. I have a few pieces of Winchester brass from the factory rounds I bought to get me shooting, I loaded the exact load in the Winchester brass and shot those as well. The first thing that got my attention was the ejection pattern, it was all over the place, one went straight out at 2', another at 4:30 at 8' and one somehow went to my left at about 2' away. I picked up the brass to examine the primers and they looked good, but the shiny ring at the head of the case got my attention. I took them inside and did some measurements and they expanded from .393" to .397'. This seems excessive to me. Am I worrying over nothing here or is this a bit much? I measured the new Starline cases and they are .397" at the head right out of the bag. If you have any suggestions I welcome them, Thank you

[Texas Sheepdawg]

I reloaded my first 450B rounds today, I chose to start cautiously and work up as I've learned to do with other calibers. I loaded new Starline cases with 35.0grs. of Lil'gun, 250Gr. Hornady FTX bullets, lit by CCI 400 primers I used a Lee factory crimp die set to .477", my C.O.L was 2.225". Everything went fine, all the rounds chambered, fed, and ejected at 3 O'clock 6' away. I have a few pieces of Winchester brass from the factory rounds I bought to get me shooting, I loaded the exact load in the Winchester brass and shot those as well. The first thing that got my attention was the ejection pattern, it was all over the place, one went straight out at 2', another at 4:30 at 8' and one somehow went to my left at about 2' away. I picked up the brass to examine the primers and they looked good, but the shiny ring at the head of the case got my attention. I took them inside and did some measurements and they expanded from .393" to .397'. This seems excessive to me. Am I worrying over nothing here or is this a bit much? I measured the new Starline cases and they are .397" at the head right out of the bag. If you have any suggestions I welcome them, Thank you

Thanks for the email. I have been working my rump off during the holidays and haven’t been paying much attention.

I’ve had a a few rare occasions where my cases swell up but it’s usually due to the powder charges I’m experimenting with.
I’m going to let someone else field your question because I’ve not had much time to do any bench work.
In all honesty, I had almost zero bench time for my 450B in 2023.
So I will let our members respond.
Thanks for joining.
Nice 4 call sign. Mine is a 4 call sign too.
73s
Rob

[KG4EIQ]

Thanks, I appreciate the response Rob. Yep, we'll wait it out and see if somebody comes up with an answer. it was just worrisome to see that much expansion on a case. I've always heard .001" was about the upper limit, anything past that you are living in a dangerous territory, and that shiny ring around the head got my attention pretty quickly. So for now, I'm going to stay with the Starline brass, it hasn't given me any of the pressure signs that I saw with the Winchester. What part of the world do you reside in? I live in north central Alabama, the town is called Ohatchee. I have run into several hams on a few forums, it's always a pleasure to meet a new one.

[coyote wacker]

I have never ever shot a single round using lead-core bullets....but not having any way to do a pressure check with a instrument reading and getting a "ring" near the base of a case I would be backing down and looking why your getting a "ring".....
First I would check OAL of a case the 450 Bushmaster doesn't like to be to short and also cases tend to get shorter with every firing....some can only be used a couple times long before the primer gets loose....your cases might be to very close to being to short to start with even once fired....

Have a 50 B&M SS built on a Winchester 70 CFR action its a straight wall case I have brass that has been fired 21 times and has been trimmed several times and the primer is still tight running load just over 60'000 psi....but the gun is CRF holding the cartridge firmly when firing ....unlike a AR-15 or any of the other factory gun built for the 450 Bushmaster except the Ruger 77 that does hold the cartridge when firing ....basically others have a small weak extractor holding it where the firing pin can push the cartridge forward for a milla-second before ignition crushing the mouth of the case shorting it....got to remember the 450 BM is a low pressure cartridge 38'000 psi it will not stretch unless you push it up in a bolt action then its going to stretch....

I've want to experiment with a Ruger 77 450 Bushmaster from Randy's to see if brass last longer I know it should because mine and everybody that has a 50 B&M SS it does....did have a left hand Ruger 77 in 450 Bushmaster but sold it before even putting a round threw it.....sold it for $2400 and would much rather have a 1-24" twist than the stupid 1-16" that people are using....

[Texas Sheepdawg]

Thanks, I appreciate the response Rob. Yep, we'll wait it out and see if somebody comes up with an answer. it was just worrisome to see that much expansion on a case. I've always heard .001" was about the upper limit, anything past that you are living in a dangerous territory, and that shiny ring around the head got my attention pretty quickly. So for now, I'm going to stay with the Starline brass, it hasn't given me any of the pressure signs that I saw with the Winchester. What part of the world do you reside in? I live in north central Alabama, the town is called Ohatchee. I have run into several hams on a few forums, it's always a pleasure to meet a new one.

I’m in Texas, but I kept my 4 call sign. (Cordova TN originated). I wanted to keep the call signed because I was very active in western Tennessee emergency management and fire and law-enforcement at the time. Everybody I spoke to said they would remember the call sign if they ever heard it again even if I moved to Texas. I left Tennessee in 2001 right after 9/11 to go to work for Plano independent school district in Plano Texas. I currently work for a water municipality in the north Texas region and have been for 19 years. I could retire in two months if I wanted to. But I think I’m gonna work a few more years.