Die question.

[Bart B]

Some years ago, a batch of Lapua .3092" 185-gr FMJRB match bullets were checked on an optical comparitor. There were four distinct ogive shapes; proof that four different pointing dies were used at Lapua and the bullets from each one were all mixed together and boxed with the same lot number. Shame on you, Lapua.

Once sorted out bullets with the same ogive shape were spun in a Dremel Tool's collet made to hold them and the current drawn by its motor was noted; low current meant the bullets were perfectly balanced; higher current meant that bullet was unbalanced. Some of the bullets were so unbalanced they flew out of the collet bouncing off walls and the ceiling of the shop. The pefectly balanced ones shot under 1.5 inches for 10-shot groups at 600 yards. The unbalanced ones would shoot up to about 12 to 5 inches. No wonder 3 or 4 bullets from a box of them would shoot very bad. Again, shame on you, Lapua.

 

[RTK]

A very common thing with reloaders; it happens a lot. With all due respect to folks who've tried full length sizing and never got the accuracy neck sizing produced for them, it's been my experience that after learning their set up and process details using a full length sizing die, they typically set the fired case shoulder back too far. And that's an accuracy killer for sure.

Not saying you are wrong but on my 22-250AI and my 300wm I haven't seen any better accuracy. I do bump my shoulder back on the 300 every few reloads because of hard closes. As I mentioned before, years ago I couldn't even find a FL die for the AI and 1/4 MOA groups for a varmint getter was more than enough accuracy for me.
I will do some experimenting with FL sizing on the 300wm in the next few months to see. I'm not too proud or too smart to try something new and learn.

 

[Bart B]

I will do some experimenting with FL sizing on the 300wm in the next few months to see. I'm not too proud or too smart to try something new and learn.

Good idea. Here's some info I'll pass on based on reloaders experience with belted cases beginning in the late 1950's when really good 30 caliber match bullets were finally available from Sierra Bullets.

Top long range competitors shooting 30 caliber magnums learned that new cases shot more accurate than any sizing method on fired cases produced. The problem was the tiny ridge right in front of the belt caused by the case body expanding between the belt and the ridge in the chamber a few thousandths in front of it. That ridge interfered with how the back end of the case fit the chamber. So a couple of folks cut the middle section out of a standard full length sizing die, squared off its bottom then used it to size fired belted case bodies all the way up to the belt after using a standard full length sizing die with its neck lapped out to about 2 thousandths inch smaller than a loaded round's neck diameter. In other words, they returned the fired case back to virtual new case dimensions except for the shoulder which was set back only a couple thousandths so the belted case would actually headspace on the shoulder. Virtually all the matches won and records set were from fired cases so sized.

Some of the US military rifle teams tried reloading their 30 caliber magnum fired cases with traditional full length dies alone and got poor results. So they just used brand new cases winning all sorts of matches and setting records with them.

Innovative Technologies now has a collet die to size the ridge down on sized fired cases. Innovative Technologies - Reloading Equipment has info on it. And either Redding or RCBS make excellent full length bushing dies for reloading belted cases along with the Larry Willis collet one.

 

[RTK]

Thanks for the info, I will look into the collet die thing. Using my current FL die looks like it will defeat that purpose.