Seating off the lands

[jcinnb]

My rifle is a CZ 527 varmint. So far I have not been able to satisfactorily seat bullets off the lands using case to ogive measurements.

I have: Hornady OAL gauge, a Hornady Comparator,and so far I’ve tried Sierra 32 gr and Berger 35 gr.

I have measured length to ogive with both bullets, many times, and get consistent results. I’m confident I’m getting the proper length. I’m taking .020 off the lands when setting up the seater die.

But, when trying to seat the bullet to that length, the bullet is barely in the case. Much less than a bullet diameter which I understand is the minimum.

Is the 527 and bullet combo a non-starter, or am I doing something obviously wrong? Thanks in advance.

[Rick in Oregon]

Do some reading here, as there's been many posts about the fact in a factory 204 Ruger barrel, it's impossible to reach the lands, as the SAAMI freebore is right at and sometimes over .100", making it virtually impossible with any .204 bullet.

All my factory 204 barrels work best with either the 32gr bullets or the 39gr SBK. Forget any of the 40gr bullets unless you rebarrel, as the 12 twist just will not stabilize them, period.

The only rifle I'm able to reach the lands is my M700 with a 11T Pac-Nor Super Match cut with my own reamer from PTG as a "Match" reamer with all dimensions tightened up to attain the "match' moniker, shown below. This rifles easily shoots under .2" at 100 yds.



Note this is a match chamber, only .015" of freebore, the neck I.D. is .230" and not the factory .234" dimension so if used, one must be careful and shooting factory 204 ammo is not recommended, only handloads. Not an issue for me, as I never shoot factory ammo anyway.

So if you want to reach the lands for accuracy reasons, it requires a new barrel of at least 11 twist for stabilizing those 40gr bullets and a chamber cut with a non-SAAMI reamer. Dave Kiff at PTG is the best source IMO.

But in reality, most factory 204's seem to shoot very well with the tremendous freebore, so you might want to try working up a good load with your factory barrel, as our friendly postal matches shot here were shot with factory barrels in factory rifles.

[jcinnb]

Thank you. I thought I had read something along those lines, but must have not searched on the correct terms. I tried. I appreciate your detailed response. Happy New Year!

[Rick in Oregon]

Happy new year to you too!

Let us know how your quest goes, and remember we're visually oriented here, so gun porn is highly encouraged.

[Jim White]

I imagine that large freebore is one of the design functions for the 204 Ruger's performance. I use 39 SBK and I can get groups in the .2 and .3 inches at 200 yards.

My CZ shoots the 40gr ok but not great. My Remington 700 204's don't like them at all. Don't be afraid to try different combinations, including powders, bullets and neck tension [I'm presuming you reload]. If you're using factory, you're at the mercy of that particular LOT of the brand of ammo you're testing/using.

Hope this helps.

[Tom Kat]

If memory serves, on my 527 the OCL for a 35 gr Berger is 2.240

But that's the memory of a 62 year old man! The guns shoots decent with that load but seems to really like the 32 gr vmax better.