I've been working up loads and getting familiar with a Ruger #3 in .375 Winchester (formerly in .45-70, but I had the barrel changed out).

In getting the shotgun patterns down to groups I've been playing with 3 moulds and a couple of powders.  The bullets a bevel base Lee, a Lyman 375499 shank opened to plain-base and a Saeco 571 (250, 280 or so and 300 gr).  Been using 18gr of 4227 and 21.5gr of Reloader 7.

One observation I made was that with one of the bullets seated to varying lengths that one of the lengths grouped about 1/2 the size of only 1/10" different seating.  In general seating out longer was much better.

So I'm down to about 2-1/2" groups (OK at this stage of development for a light weight carbine off a sandbag with a 2-1/2 power scope at 100yds.)

Do y'all start with a given seating depth or do you tune it when you come to a close shooting group?

Cat_Whisperer wrote on Mar 15^th, 2014 at 9:05pm:


I let accuracy determine COAL. Very simple formula.   

        Joe. 

I'd start with a cartridge that is just short enough to chamber, then work my way down. May not work in some, but worked for me in my 45/70.

Ciao998 wrote on Mar 15^th, 2014 at 11:27pm:

I do the same except start at the longest OAL that chambers easily and doesn't de-bullet as the unfired ctg. is removed from the chamber. 
I haven't yet found a ctg. OAL greater than that = WILL de-bullet, that had better accuracy.
I find that that no de-bullet OAL changes fast as the rifle is fired with lead bullets only, .075" in ~2000 lead bullets fired in a .223 Rem with 8/IMR4227 and 225415 as the average load. 
I have found little accuracy difference within, say, .050" less than the no de-bullet length-I'm sure that others will strongly disagree.   
I'd like to see data.
So, once the secret OAL is found, if found, it will lengthen as shots are fired, even lead.
I once believed that lead bullets didn't wear a barrel, but  see that small powder charges and lead wear at least the lead/throat/free bore/ whatever we call the place between neck and bore.

Elk, Deer, Bear, Moose, Buffalo, Rabbits, Antelope, at one hundred yards, 2 1/2 is perfectly adequate.  

       Joe.

I actually have 3 rifles.  Two are R#3's the carbine is easiest to shoot from the bench the other is fully Scheutzen - palm rest and hooks.  The other is a Win 94BB.

The process here is to develop a method of fine tuning.  One group of 4 in 1-1/2" (plus a filer that I could have thrown) tells me there is potential for doing better (as I was moving in 1/2gr increments and paying little attention to seating depth).

When I get close in and repeatable, I'll fine-tune for the other two rifles as well.

Icey this week.  Hurry up and wait.

CW still trying to figure out if you are talking fixed or breach seated. If breach seated when moving the bullet further in you are at the same time creating more volume and thus you have to add more powder to stay in tune. The same would hold true if you are reducing the seating depth thus reducing the volume as well. I hope this helpful as it is often times over looked during the load development stages. 

JLouis

JLouis wrote on Mar 17^th, 2014 at 3:43pm:


For now fixed.  Fixed with two of the bullets, the third (Saeco) is tapered - I'm sizing it for fixed and when I get to it, I'll leave it tapered for breech seating with the R3 that's set up for it.