I measured my Ruger No.1 375H&H COL with a Swift 300gr. A Frame at hitting the lands at 3.650
Ok that leaves the ?crimp ring? on the bullet exposed.I'm not going to crimp.
1.Does the ?crimp ring? exposed make any difference?
2.How long of a COL should I start with if hitting the the lands is 3.650? I was thinking about 3.635 or should I try closer or farther first?

Doesn't matter a bit where the chanelur[spellings not good] is in the ctg. I would start right where the bullet is when the ctg. is jammed into the chamber. Work out and in in .005 increments.

Ok thanks!

If you are making hunting loads, I would back off the lands by about 25 to 50 thousands depending on the bullets used..With any monolithic I would always back off 50 thousands..I pretty much back off 50 thousands in all my hunting loads and I still get inch groups.

Bench rest is another matter where .001 could make a difference in group size...

rws2,

You are using a Ruger #1 so magazine length isn't critical here.....

The maximum recommended catridge length for the .375H&H from a number of reloading mannuals is 3.60" so you are already .050" over this length when at the lands with this particular bullet/cartridge/rifle. Net, I'm not suprised that the cannelure or crimp grove on the bullet is exposed and NO it doesn't make any differnece with this load.

I agree with Ray 100% that hunting loads should be off the lands by at least .030"-.050" for a whole bunch of reasons but primarily that with modern smokeless catridge/powder/bullets pressures will rise in a big hurry when heat, crud and ammunition handling are involved in a not so sterile hunting environment. Typical also of the .375H&H is that depending on what powder you are using, whether or not you crimp (you said - NO), powder selction (bulky powders in the .375H&H can cause bullet pull), so the cartridge could actually "grow" in length after being assembled.

Net, without all the "Who shot John & Uncle Bill Cobbley"; this isn't a benchrest catridge, action or barrel so a couple of hundredths SHORTER isn't going to be crucial, and you're still discussing a longer length than normally recommended anyway. I'd load to 3.60" (where the cannelure will probably be about right for the cartidge length anyway).

Cheers,

Gerry