Is there a max. brass neck expansion number?

[billmo]

Upon firing, is there a max. expansion of neck size allowed? This would have to be a spec, for chamber neck maximun size allowed.
The caliber in question is 22-250 Rem. Thanks for your comments. Bill

 

[Travelor]

I've been trying to educate myself on this very issue lately due to a new gun. I an not able to contact the builder,Speedy Gonzales) as he has closed his shop and I do nto ahve a new contact address/phone number for him. I have heard he is now teaching gunsmithing in Clorado.

According to the BR guys that I ahve read on this subject, the neck size of the case vs. the chamber should be around .001" under. Allowing for some spring back, the fired case should show and expansion of about .0005". BUT, they also say that up to .003" is OK for a non-BR gun. Do not expect to see this on a factory gun as they are built to accomodate a large variety f cartridges from differnet manufacturers.

I just purchased a "no turn" chambered 6mmBR that is showing the .0005" neck expansion. The fired cases are showing such a small expansion that they do not allowed a bullet to be hand pressure seated in the fired cases. I have neck turned some cases by .0005" per side for a total of .001" and the bullets just barely seat with hand pressure in these cases- probably a much better thing.

Hope this helps.

 

[billmo]

Traveler, Thanks for the reply. This rifle that I have purchased is a 22-250 in the Savage LRPV. I set it up and was breaking the barrel in yesterday and noticed that upon firing and removing the case that it was expanding to @ .007 more than my loaded round was measuring. Those numbers being .248 loaded round and .255 after firing. This seems excessive to me. This is new Norma brass and had never been fired. I also noticed that when I run the brass in my Redding FL bushing die set up with a .247 Tin bushing to neck size and bump shoulders, that portion of the
case that was sized has from .005 to .006 runout. The balance of the neck is running .0005 to .001 on the gage. I was thinking that with the chamber being that open in the neck area and moving the brass that much may be why the sized portion of the necks have so much runout. All comments appreciated. Bill

 

[treeman]

just wondering if you have checked the runout on some fired casses? treeman

 

[billmo]

Treeman, Yea, I did and the runout out before sizing is .0005 to .001. like the remainder of the neck.

Catshooter, I did not know what max chamber neck deminsions were.
Thanks for that info. Yea, I am familiar with tightneck chambers and that would be a problem for sure for factory rifles.

So in your opinion, just neck size like I am doing? Take the expander ball out or leave it in?. Get a neck sizing only die? The other problem that I am having is even with the die backed out from the shellholder, the brass is being reduced so much,.007) that it is moving the shoulders back .004 to .005 without trying. Thanks, Bill

 

[Preacher]

Travelor..
Your going to have to turn those case necks down a little more, you should be able to easily seat a bullet by hand in any case you have just fired, your going to have higher pressure problem if you don't.....
I like to hear a little pop sound when I pull a bullet out of a fired case, no more, no less.....
When you have it perfect you can push the bullet down into the case and air pressure will push it back out a little until you loose the trapped air...........

 

[billmo]

gunamonth and catshooter, thanks for the help. I believe preacher was referring to another earlier post. Anyway, I am lubing my cases, my bushing is floating, and I am going to order a .248 bushing and try to find some thicker brass as I would like to decrease some of this movement of neck brass. I did try with and without the floating expander ball and saw no difference
with sizing last night. Not to say that it does not make a difference cause I know it does in most cases. You are correct with the neck wall thickness, gunamonth. Thanks guys for your assistance. I would really like to make this work without sending the rifle back to Savage because as you pointed out Catshooter I may just wind up with another chamber with the same neck specs. in a factory rifle. So, I am going to try to work with what I have and see what kind of accuracy I can get out of this rig. I had rather at least try before I start harping on the manuf. Bill

 

[billmo]

I really appreciate you guys patience while I try to learn more about this reloading game. Great bunch of guys to talk to and LEARN from. Thanks, so much. Bill

 

[mrjdasr]

what is your guess on brass longevity with this much expansion & resizing. are split necks going to be a problem?
I have a similar situation with a dasher chamber that i did by running a 243 ackley reamer in short. got new lapua brass with 270 od necks and a chamber with a 276 neck. havn't fireformed any yet, don't want to waste the expensive brass.

 

[billmo]

msjdasr, I don't know for sure but one of these guys will answer that for you I'm sure. These guys know what they are talking about and will not tell you something wrong. They are far better qualified than me. Bill

 

[mrjdasr]

my "large neck" is temporary anyway got a 6brx reamer ordered from PTG. going to cut a little off the barrel & rechamber
the dasher was just an experiment to see if it could be done.
made my brass from some unfired 25/06. that took a lot of resizing. thanks for the answers its good info for the future

 

[Stonewall]

billmo I would sent a few cases to Forster and get them to make you a FL die matched to that chamber . Then you can size that brass with no expander ball etc.

I've used these dies with several large neck factory chambers and have seen minimum run out. ie 7mm Rem with .011 clearance
and a .22/250 chamber using the same brass and dimensions as you .



http://www.forsterproducts.com/Pages/dies.htm

Glenn

 

[billmo]

Don't think I've ever disagreed with Preacher but the time has come. Unless the brass has some serious variations in wall thickness I wouldn't turn the necks. You've already got more clearance between the neck and chamber than you want.

Eight thousandths sizing is a lot to ask of a bushing die. You might get better results if you did it in two steps... like a 0.251 bushing first then the 0.247. A couple other things... make sure the neck is lubed. There is a tech bulletin on Reddings site that says for best concentricity, use lube even with the TiN bushings. Second, make sure the bushing is free to float. If it's held tight and not centered it will be out of round every time. Get rid of the expander too. I also wouldn't use a FL die. It's equivalent to shooting new brass every time.

The easiest way I've found to get concentric loads when there is a sizable difference between the chamber neck and loaded round is to use a Lee Collet die. The disadvantage is you no longer have control over neck tension.

If my math is correct, your Norma brass has neck wall thickness of about 0.012". You might be able to find another brand with something closer to 0.014" which should help some. If I have a chance I'll measure some of the various brands I have and let you know what I find...

Gunamonth and Catshooter, got me some new brass yesterday and now my loaded round is measuring .252. That seems like it would work better considering that my chamber neck is fairly on the open side. The closest bushing I have to .252 is a .249. Would you try that or go to a .250 or .251? Thanks, Bill

 

[billmo]

Well, I think I'll try the .249 and see what happens. If it is too much then I might borrow one to see if it makes a difference. Thank both of you for your comments