I guess I should include that I have started prepping cases and getting measurements. For starters I bought some Sierra 140 grain Pro Hunters. I bought Hornady dies, so I do have some 139 grain BTSP coming. I wish they would send out the flat bases as I hear most of the time flat bases are easier to get good accuracy up to around 300 yards. Plus, that is the bullet Hornady uses in their factory ammo which seems to shoot very well.
Seeing how I am going to limit myself to 300 yards on big game out west, and rarely have a shot over 200 yards here in Arkansas, I thought flat bases would be the way to go. But, maybe the boat tails will work out fine for me.
I did take a fired case, slightly size the neck, and stuck the Sierra bullet in it to get a OAL. I measured it quite a few times and always came up with the same number - 2.757". Sierra load data listed their OAL at 2.780", so I know I will have to start low and work up for sure. I will have to say that I was a bit perturbed when I called Sierra about this, trying to see if they had any idea of a correlation between my seating depth and how it will effect pressures. The guy on the phone, older gentleman, acted like I was a complete idiot and did not present his company in a very good light. I have had past dealings with them that were good, so I will write this one off as a grumpy old man day.
Needless to say, this gun has a very short throat/leade. I think the only reason why the Hornady ammo shot good was because their bullet secant ogive is significantly different than other bullets in the same weight class. I'll have to wait till I get some of their flat base bullets to see, but I bet I am not far off the lands with that factory ammo. I do remember some guys posting about how their Ruger Americans were hard to close the bolt on with other factory ammo. I have to wonder if it is not because of the short throat. Its definitely something you don't think about normally, but I can see how it would happen.
I am not 100% positive just yet, but I think that the chamber is on the small/tight end of the spectrum too. I use the Lee trimmer, which I found does not quite get the cases cut down to recommended length. It was cutting them down to 2.030", recommended being 2.025". Well, I tried to chamber one of these last night and the bolt was VERY hard to close. Actually, it did not want to close at all, and I would probably never shoot a round in a gun that I had to close the bolt so hard on.
I marked the end of the case mouth with a sharpie and it was smeared off when I took the case out. I am going to trim down the Lee trimmer pilot so that my cases are 2.025" and then see if the bolt sticks again. I could not see where it was hanging up anywhere else on the case though.
My desire would be to find a load with H4895 since I use that in a few other cartridges, and I have always wanted to find a powder I use a lot of to justify buying in bulk. But everything I hear is that H414/760 is tried and true. I can work around any temp issues it may have.
I'll for sure give updates as I go along. I'm sure I'll have some pictures too. Looks like rain all weekend, but if it breaks I'll get out and do some testing.
