264 Win Mags - When would the brass cases be considered "Fire Formed" for each individual action?

Darkside

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Unknown Munitions has had 264. brass for a while. If you need brass.
 

cape cove

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I have 5 belted mags and most of the time it has taken me at least 2 firings to fully fireform my brass to the point where the shoulder has to be bumped for good chambering.. But what @entoptics posted concerning jamming a bullet seems to me like a great idea. I never in the past took into account the belt tolerance. I will most certainly take this into account in the future. TKS
 

sesauk

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Actually, for good case life, forget about the belt. Fire form, resize and set to the shoulder like a regular unbelted case. Cases will last much longer. About 2-3 firings and you're all set.
Yes, I am planning on using the shoulder to set everything up. I have a special tool to resize the belt if they start to swell. Thank you for the information
 

sesauk

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Brass for 264 Win Mag is easier to obtain than one might think. I prefer to neck down 7mm Rem Mag brass. It's very simple to do. Neck down and shoot. High quality 7mm Rem Mag brass is more available and much less expensive. I went from Nosler Custom 264 Win Mag brass to Peterson 7mm Rem Mag brass and never looked back.
I love that idea.
 

sesauk

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In my experience with belted magnums (264WM, 7RM, 300WM), the base to shoulder on virgin brass is VERY short. My 264WM grew over 25 thousandths on first firing with Winchester brass. My ADG 7 rem mag brass grew 15 thousandths if I remember correctly. These were both in minimum head spaced X-caliber Savage prefits.

With that much stretch happening, it might be good idea to "fire form" with a jammed bullet for the first firing. I did this using some relatively cheap bullets and a mid-level load. One firing got the brass near enough to its full size, with almost imperceptible growth after the second firing with a "normal" load.

If I were you, I'd at the very least check the growth. Measure a virgin piece of brass from base to shoulder, then fire a couple and measure. If the growth is extreme (>0.010") it might be worth using the jammed bullet method, which forces the case head to rest against the bolt face. Otherwise, the brass will stretch backwards and forwards, instead of just forward, potentially thinning the case walls at the web. If the rifles are good shooters, you'll likely get good accuracy out of the fire forming loads, so use them to plink around, get your scope close, break in the barrel, and just have fun.

After the first firing, you'll be able to adjust your die so that you just bump the shoulder back 0.002" or so, and subsequent firing cycles will result in FAR less case stretching, and therefore considerably longer brass life. A small shoulder bump is also probably better for accuracy and precision.
Thank you for all of the information I am getting the Zero reloading press for Christmas. I already have redding dies I also have the competition shellholder set that will already make the shoulder bump 5-piece set from 0.002 to 0.010. The LarryWillis.com Belted Magnum Collet Resizing Die for all belted magnums. I am trying to do everything right.
 

sesauk

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Brass for 264 Win Mag is easier to obtain than one might think. I prefer to neck down 7mm Rem Mag brass. It's very simple to do. Neck down and shoot. High quality 7mm Rem Mag brass is more available and much less expensive. I went from Nosler Custom 264 Win Mag brass to Peterson 7mm Rem Mag brass and never looked back.
Can the 300 Win Mag be resized to the 264 Win Mag?
 

sesauk

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My experience with the 300wm is that it is dependent on the brass as well. I have seen that cheaper brass will fire form in 1 firing, but I have some new Lapua brass that is on the 2nd firing and I still haven’t had to set it back yet. I have been firing and full length sizing, but all pieces fit perfectly without the 2k setback yet.
Can you resize the Lapua 300 Win Mag to a 264 Win Mag?
 

QuietTexan

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I pick one case to fire. I reload that one case at the range until it starts to show wear
And that's the only way to know when your brass is formed and how long your brass will last - actually shoot a case until it needs to be sized, and continue shooting it until it has problems or you hit enough firings to not have to worry.

I took a 243 AI case to 14 firings and gave up because the barrel probably isn't going to last 2000+ rounds it would take to shoot all my cases that many times.

Oddly enough this is the correct way set a sizing die to resize shoulders - there's no "bumping" a once fired case because you have no idea where the growth actually stops. Spend the 5 minutes it takes to strip the bolt and test fit once-fired brass that was only neck-neck sized and if the bolt drops, it doesn't need bumping or body sizing.

OMG he said neck-sizing 🤣
Angry Black Friday GIF by Buyout Footage
 

Huntsman66

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Can you resize the Lapua 300 Win Mag to a 264 Win Mag?
I wouldn’t be the best guy to answer that for you, as I have never done it, or even looked into it. Maybe one of the other members have experience with that and can chime in…..
 

AntsRick

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Can you resize the Lapua 300 Win Mag to a 264 Win Mag?
It is feasible but not a simple “run 300 brass thru a 264 size die” operation. 300 WM brass is 2.620” base to mouth; 264 chamber is 2.500” +~0.010” maybe! So trim case length is imperative.

300 WM case body (base to shoulder) is longer than 264 WM so shoulder must be pushed back. I’ve not attempted necking down 30 cal to 26 cal in one operation but suspect success would be <100%, at best, with standard size die.

My experience with pushing back shoulder of 300 WM case is limited to using an rcbs-made form die first to establish necessary body dimension, then full length size to adjust neck (but this was with a wildcat that didn’t require trimming case length since longer neck was part of the goal). 338WM, 7mmRM & 264WM base to shoulder dimensions are very similar if you have access to either of the other 2 size die maybe it could be done without the form die (remove expander/decap rod). I believe the 7mmRM die may achieve starting the neck-down & push shoulder back in 1 operation but skeptical about wrinkling shoulder in the size die. Suggest experimenting with cheaper brass. However, if it’s used brass, hardness may affect results.

It’s been a few years but I recall imperial wax, judiciously applied, being far superior to spray case lubes.

Good luck if you attempt it.
 

ThrdKllr

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You can make them with 300 win mag cases but it’s a lot of work. I made some for my 7mmRM out of 300WM brass but you definitely have to turn the necks after being sized and trimmed. DO NOT USE THE Decapping/Expander rod when forming the brass.
 

sesauk

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Thompson Falls Montana
It is feasible but not a simple “run 300 brass thru a 264 size die” operation. 300 WM brass is 2.620” base to mouth; 264 chamber is 2.500” +~0.010” maybe! So trim case length is imperative.

300 WM case body (base to shoulder) is longer than 264 WM so shoulder must be pushed back. I’ve not attempted necking down 30 cal to 26 cal in one operation but suspect success would be <100%, at best, with standard size die.

My experience with pushing back shoulder of 300 WM case is limited to using an rcbs-made form die first to establish necessary body dimension, then full length size to adjust neck (but this was with a wildcat that didn’t require trimming case length since longer neck was part of the goal). 338WM, 7mmRM & 264WM base to shoulder dimensions are very similar if you have access to either of the other 2 size die maybe it could be done without the form die (remove expander/decap rod). I believe the 7mmRM die may achieve starting the neck-down & push shoulder back in 1 operation but skeptical about wrinkling shoulder in the size die. Suggest experimenting with cheaper brass. However, if it’s used brass, hardness may affect results.

It’s been a few years but I recall imperial wax, judiciously applied, being far superior to spray case lubes.

Good luck if you attempt it.
Thank you for the insight
 

baldhunter

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A 264 Win mag is a 338 Win Mag case necked down.A 7mag is a 338 Win Mag case necked down.A 300 Win Mag case is much longer,the shoulder is way farther forward and is not a good case to make a 264 Win Mag case.The shoulder would have to be pushed way back and totally reformed in the die.This would also leave you with an extra long neck that will require a considerable amount of trimming.Your best choice is find 264 Win Mag brass.Your second best choice is neck down 7mag brass.
 
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