Chamber Question

[winmagman]

Since I know nothing about chamber specifications I thought I'd ask you gents for some help. I measured a new 300 win mag case right in front of the belt (.509), at the end of the neck (.335 O.D.), and for oal (2.612).(This is a loaded Win. Supreme round)Next I measured several once fired cases in the same way, in front of the belt,(.512)at the neck,(.341 +or- .001)and oal(between 2.615 and 2.623). I'm about to jump into reloading and am trying to decide weather to full lenght size or just neck size. I've heard that in a tight chamber it is better to just neck size so finally to my question can you tell from these measurments which route I might have more luck with?
Thanks
Chris

 

[Guest]

I copied this from another post, but I think it applies. You should full length size.

Most guys that neck size only, do it because it works better for them. I know that many of these guys have had a bad experience with full length sizing, usually caused by the die that they purchased not matching their chamber properly, or concentricity issues caused by expander balls, or poorly made dies. The other common issue is headspace problems caused by not setting the die up in the correct position. This group is usually mislead by a die that is stretching the cases as they are pulled out of a poorly polished die, so they screw the die in until the die cannot stretch the cases beyond what they have pushed the shoulder back. Of course this creates excessive headspace on some cases and overworks all the cases.

Accuracy is the best with brass that is full length sized, but the dies must be made properly and set up properly so as not to overwork the brass.

 

[winmagman]

Thanks S1.
I've got one more question. What do you think of the Innovative Technologies Belted Magnum Resizing Die? Is it worth the extra money? (OK 2 more questions)
Chris

 

[Guest]

I know nothing about that design, and have never used one.

 

[dbhostler]

winmagman,
I have used the IT die for about a year now and it does what it claims to do. However most would say it is not necessary unless you use the same brass in various rifles or are reloading for an autoloader. A FL die should resize above the belt enough to allow your case to chamber easily. The IT die is pricey, but of very high quality with immaculate machining.
I usually FL resize first, and then IT it. Works great and chambers like an unfired case. I have probably reloaded this brass ten times and no sign of seperation above the belt. By the way, my 7 Mag shoots better when I FL resize as opposed to NK sizing.
Good Shooting,
db

 

[winmagman]

Thanks for the input db.
I'll have to do some more thinking on this one. Maybe I'll wait and see how things work without it first. (just getting started reloading.)

 

[deergrunt]

I full length resize new brass or range brass that I picked up from the brass bucket. Once brass is fired from my chamber I only neck size. This works for me.