Bolt HeadcFitting Question

[Bindi2]

Just be aware that to tight is just as bad or worse than too loose. The .064 to .074 allows for rim thickness which does vary quite a lot.
If reloading for more than one rifle keep the brass for each rifle separate from the others use a LEE Neck sizing die only until a Full length sizing is required then only the minimum amount needed to chamber testing for case head separation before each reloading. That is before primer ,powder, projectile.

[Alan de Enfield]

Just be aware that to tight is just as bad or worse than too loose. The .064 to .074 allows for rim thickness which does vary quite a lot.
If reloading for more than one rifle keep the brass for each rifle separate from the others use a LEE Neck sizing die only until a Full length sizing is required then only the minimum amount needed to chamber testing for case head separation before each reloading. That is before primer ,powder, projectile.

That is a very valid point - setting your headspace 'tight' to work with a SAAMI case with a 58 thou rim, then try and use a 'proper' military spec round with a 63 thou rim and you'll not be able to close the bolt

[Claven2]

I think segregating brass is worthwhile if you shoot multiple 303 rifles regularly and if you don’t have large supplies of brass.

I have one set of brass for a rifle I shoot regularly and size gently, and another set that gets full length sized and used in whatever rifle. Those cases give fewer reloads, but it’s convenient and I have lots of brass.

[CINDERS]

I used to separate my brass then just neck size, but when you have a number of 303's your fueling it gets tedious.
What I found is my reloads whilst close to the MKVII specs they are not hot by any means and still fairly accurate good enough to win a 3 range multi-position match anyway.

I FLS all of them now but have found annealing them before sizing with my AMP machine seems to work in relation to brass longevity as it has been a fair while since I had a H/Sep probably get one this w/end but one always carries a B/C extractor.
Some rifles do seem to have a maybe slightly larger chamber as exhibited by a ring just above the web of the fired case I am fairly lucky as none of my shooters exhibit this fact.