TOO Tight bushing??

trevort · Post by **trevort** » Tue May 29, 2007 11:57 pm

I got a .267 bushing for my 6/250 neck die. On Shane's advice i got a .266 aswell. he said try it if the .267 doesnt give the results I want.

The throat is cut to optimise the rifle for the 70 NBT but wouldnt you know it the most promising groups so far are with the 65 vmax.

There is just 4 mm of the bearing surface of the projie (excluding the boattail) in the neck of the case to give this round the same oal at the ogive as the 70 NBT.

Thought I would try one group of the best load so far with the tighter bushing. You can actually see the neck looking flared from the projie base on up and a little ripple where it goes back in to its sized dimensions after the projie ends.

Would you agree this bushing is too tight? (I suppose I could only size the first 4 mm if these turn out to group better) I am assuming there would be no danger with these rounds and the main risk would be losing cases to split necks?

Kenny · Post by **Kenny** » Wed May 30, 2007 10:10 am

Trevort,

Mate if it works I don't see any probs, maybe she just loves that neck tension

you won't know till you try it.

The cases might not last as long due to the overworking of the neck as you say...but when you think about it the rest of the neck expands to the chamber when the shell is fired anyway.......

KY

Ned Kelly · Post by **Ned Kelly** » Wed May 30, 2007 10:12 am

G'Day trevort,
what is the diameter at the neck where the projectile is seated?

For example, if it measures 0.270", use a 0.268" bushing. I like about .002" tighter than the loaded round diameter for BR/Fclass. For a hunting load you may like to use 0.003" tighter fit.

Cheerio Ned

trevort · Post by **trevort** » Wed May 30, 2007 12:04 pm

Ned, dont own a micrometer so these taken with digital verniers. Case neck measures .015 (hope the decimal is in the right place. The case with the projie is .271 and measured below the projie base is .269. The neck was cut at .273

Ned Kelly · Post by **Ned Kelly** » Wed May 30, 2007 1:27 pm

G'Day Trevort,
The bushing's seem about right, especially since you are not shooting BR. Like Kenny says, the neck will expand anyway, you will have more work hardening of the brass, but it's only 0.001" (1 thou) much less than a conventional FLS or NS die would and when you resize fired brass, think of that area of the neck that hasn't been resized as an alignment aid for the case. This part of the case will help in aligning the case (& bullet) in the chamber. It's all good.

My factory 22-250 used Winchester neck turned cases (100% clean up) and the same thing occured when using wilson dies, but they lasted a good 10 firings under HOT loadings! So dont worry too much as I reckon the brass is relatively cheap part of reloading and it is prudent to replace your brass after say 10 firings just to be safe and ensure it is not work hardened too much

Cheerio Ned

trevort · Post by **trevort** » Wed May 30, 2007 2:08 pm

Thanks. I will see if the rifle likes the tighter neck tension. if not then back to the .267

jb747 · Post by **jb747** » Fri Jun 01, 2007 3:59 am

Trev, don't forget to try the Sierra 70 Blitzking. We had excellent results with them in the 6/250.

trevort · Post by **trevort** » Sat Jun 02, 2007 12:16 am

well my 204 loves 39 BKs to the exclusion of all else. My 223 loves the 50gn BKs.

When i made up dummy cases for my 6/250 before getting the chamber cut, the greater taper of the 70 BK meant it had the shortest OAL. So if i cut the chamber optimised for the 70NBT then the BK would have a big jump to the lands.

Well since I have had such great results with the BKs I cut the 6/250 for the NBTs of course

I may try them, after all they like the jump in the 204

AusVarmint

TOO Tight bushing??

TOO Tight bushing??