260 rem. 30 degree improved ? Fireform

[chukarmandoo]

I have a mauser that I had chambered to this cartridge. Here's the deal. If I don't load it to near max it does not form right and the primer is backed out of the case about .003 to .004. If I load it to near max it forms great. Thoughts? I think it is chambered .002 to long? Can this be a problem? Or do I have a wildcat of a wildcat? Thanks. Dan

[stomp442]

sounds to me like you need to seat your bullet to touch the lands so that the case is pressed firmly against the bolt face and the case forms properly.

[BillPa]

If I don't load it to near max it does not form right and the primer is backed out of the case about .003 to .004. If I load it to near max it forms great. Thoughts?

Thanks. Dan

'ol P.O. warned using a light load tends to allow the case to "bounce" when fired and results in short brass, exactly the condition your having. His instruction, "Use a good stiff load".

My advice, make sure you have a crush on the neck shoulder junction and use an upper window load for the parent then you shouldn't have any problems.

Bill

[chukarmandoo]

I understand what you guys are saying but what I'm wondering is, can the chamber be cut to long? If so where would the line be drawn as far as being safe? I don't have a comparitor but I know the chamber is longer than the parent case. Just don't know how much? Also I have been only using new brass as parent case. Thanks. Dan

[BillPa]

I understand what you guys are saying but what I'm wondering is, can the chamber be cut to long? Thanks. Dan


Well its certainly possible, but I have a few questions.

1. Is this a new barrel/chamber or one that was rechambered to the improved?
2. If you used 260 Rem brass, did you FL size it using a 260 Rem FL die?
3. When chambering the parent was there a bit of resistance locking the bolt to battery?

Bill

[chukarmandoo]

Well its certainly possible, but I have a few questions.

1. Is this a new barrel/chamber or one that was rechambered to the improved?
2. If you used 260 Rem brass, did you FL size it using a 260 Rem FL die?
3. When chambering the parent was there a bit of resistance locking the bolt to battery?

Bill

1. It was a new short chamber 260 barrel. .050 or close to that.
2. I used new 7/08 brass and I FL sized w/260 rem. FL dies
3. No.

[BillPa]

Well, first of all 7-08 brass is shorter than 260 from the casehead to the neck-shoulder junction, how cartridge head clearance (Not headspace!) is established in a improved chamber.
http://i44.tinypic.com/259anup.jpg
Using the drawing above 7-08 brass on the average is .029" shorter than 260 Rem, casehead to the junction. If you want to use the 7 brass then you'll have to create a false shoulder by partially resizing the neck for the required crush, much the same as using 222 Rem Mag brass to make 204 Ruger brass.

http://i44.tinypic.com/2ag0xsg.jpg
On the flip side you could neck up 243s, the casehead to junction length would then be the same as 260.

Bill

[chukarmandoo]

OK Bill that explains a lot. I never looked that close at the numbers. Thanks. So if I continue to go about it the same way could I run into problems? As you have shown me, that tells me why I get that step in the neck when I size the 7/08 to 260. The reason I use 7/08 is to keep from getting a doughnut in the shoulder neck junction, If that makes sense?

[BillPa]

When your brass is roughly .029" short, yeah it can cause some problems. It would be akin to shooting a 250 Savage in a 25 Souper (25-308) chamber.

I don't see a problem using the 7 brass as long as you partially size the necks to form a false shoulder. Just back off you 260 Rem die then start adjusting down it to reduce the neck OD until the bolt will lock down with a slight resistance and use a upper window load for the 260.

As far as doughnuts, I wouldn't be overly concerned at this point. If they do form it also depends a lot on the amount of freebore your chamber has and the bullets your using if they'll be a problem. If you are able to seat bullets out past the shoulder-neck junction doughnuts won't be an issue.

Bill

[chukarmandoo]

Thanks Bill !

[BillPa]

Thanks Bill !

No problem.

Oh BTW, DO NOT resize the parent cartridge in your improved FL die otherwise you'll push the junction back to the post Improved location. Remember, the improved casehead to junction length will be .004-.006" shorter than the parents's. The most you want to do is fix up the necks if needed , fire them As-Is.

Bill

[chukarmandoo]

No problem.

Oh BTW, DO NOT resize the parent cartridge in your improved FL die otherwise you'll push the junction back to the post Improved location. Remember, the improved casehead to junction length will be .004-.006" shorter than the parents's. The most you want to do is fix up the necks if needed , fire them As-Is.

Bill

I don't. Thanks for the heads up.
One more ? I haven't done this but was wondering, is it a no-no to fire form used brass?
The reason I'm asking is, say I have standard 260 reloads and I'm out of the improved loads.

[BillPa]

One more ? I haven't done this but was wondering, is it a no-no to fire form used brass?
The reason I'm asking is, say I have standard 260 reloads and I'm out of the improved loads.

I generally recommend using new virgin non FL sized brass when asked that question. If your brass has only one firing/loading cycle on it you should be OK. Where it causes problems is when the brass is work hardened from loadng/firing cycles.

Bill

[stangfish]

Bill, You did an awesme job pointing this gentleman and many others in the right direction. Good form!

[chukarmandoo]

Thanks Bill. You have passed along a lot of information. Like stangfish stated. Funny thing is, this went a whole different direction than I first thought. Thanks again. Dan