SmallCaliberCentral

I recently purchased a Sinclair Seating Depth Gauge to measure OAL's to reach the lands on my Cooper 21 (bolt action single shot). I found that the length, depending upon my bullet selection, varied from 2.384 for Sierra 39g SBK's, to 2.451 for Berger 40g Match/Varmint, to 2.466 for 32g Sierra SBK's. I regularly load in the 2.355 range, but have never gone longer. Has anyone stretched their loads out to near these lengths? I don't plan to have the bullet sitting in the barrel, but want to cut down on the "jump".

I load my Cooper (223) so that my 40 grainers are .002" off the lands. The Pet Load was worked up 'ladder' style as usual. We load all our varmint rifles long for bench varmint shooting single shot, as we can then reach the lands (except in factory 204's) and adjust seating depth for accuracy in each rifle. There's also no chasing of valuable dented brass by using this style of shooting.



That sure won't set any records, but is plenty accurate enough for our sage rats out as far as the bullet stays stable. You'll need to experiment will different depths beyond SAMMI (too short) standards in your own rifle to find the sweet spot. Cooper's are usually chambered properly, in that you should be able to reach the lands with yours, even in 204. Let us know how it goes. HTH

I talked with Rob Behr (sp?) that used to be with Cooper, after buying my first Cooper .204. He recommended oal of 2.235" for the .204. I tried it, and it works for me. We all know that measuring to the tip of the bullet isn't an exact measurement, but you can measure to the ogive with the right tools. I load all my rounds, for both guns (Coopers) to their recommended 2.235". The bullet is taking quite a jump, but it sure seems to work in both my rifles. You might try this oal and see if it works for you.