My trip to SA is in about 3 weeks. My journey getting this rifle ready has been interesting. Here is the load development part of it.
The rifle is a CRF M-70 that started life as a 375HH stainless. I also acquired a new CM factory takeoff barrel in 416 Rem and had it installed. This was in 2008, 10 years before I got my own lathe. I put it in a McMillan Supergrade stock and upgraded the bottom metal. I had it cerakoted back then, but early this year I had my shop recerakote it. I shot the rifle a little back then. This year I also added a Trijicon 1-6x24 ACOG and bedded the action to the stock.
I went to my load developer's for my first session in June of this year. I put 65 rounds through it off the bench. I tried several bullets and two powders. I quickly learned the issues with 400 grain G9 mono's in a 3.6" factory magazine. The 400 grain monos would have worked if the barrel had like IMR 4166 (H4895 speed), but it didn't. So I settled on Varget and 400 grain SAFs.
I went to a local range to fine tune, as well as shoot off sticks and shoot offhand. After two more sessions I had the load where I wanted it, but I had used up all that box of 416 SAFs. However, during the third range session, the new box of SAFs shot like crap.
The old box was probably from 1998, and the new box was much newer--I bought it from a forum member. Now I did have more SAFs on order from Swift, but it was very concerning that the new bullets shot so bad. I was kicking myself for not simply ordering a new barrel and chambering it myself. I would up talking to Bill Hober himself (a VERY nice guy). I suspected it was a slight change in bullet design, but he initially thought it was a powder lot issue, but all these loads have come from the same 8lb jug of Varget.
He then said that yeah, there has been a change several years ago. The old bullets were slightly tapered along the bearing surface, larger at the base. The new bullets were not.
I was relieved. Of course that was the issue. Bullet obturation and elongation are a huge part of accuracy. I speculated that it just wanted a little more powder, and it did. It needed a 1/2 grain more with the current design SAFs. I wound up with SAFs at 2430 fps and Swift break away solids at 2380 to have to same POI at 100 yds. In the pic, the solids are the upper left target, the other two targets are SAFs. All three groups are around an inch.
Now I just need a couple more sessions off shooting sticks and offhand, and I'll be ready. Can't wait!!
The rifle is a CRF M-70 that started life as a 375HH stainless. I also acquired a new CM factory takeoff barrel in 416 Rem and had it installed. This was in 2008, 10 years before I got my own lathe. I put it in a McMillan Supergrade stock and upgraded the bottom metal. I had it cerakoted back then, but early this year I had my shop recerakote it. I shot the rifle a little back then. This year I also added a Trijicon 1-6x24 ACOG and bedded the action to the stock.
I went to my load developer's for my first session in June of this year. I put 65 rounds through it off the bench. I tried several bullets and two powders. I quickly learned the issues with 400 grain G9 mono's in a 3.6" factory magazine. The 400 grain monos would have worked if the barrel had like IMR 4166 (H4895 speed), but it didn't. So I settled on Varget and 400 grain SAFs.
I went to a local range to fine tune, as well as shoot off sticks and shoot offhand. After two more sessions I had the load where I wanted it, but I had used up all that box of 416 SAFs. However, during the third range session, the new box of SAFs shot like crap.
The old box was probably from 1998, and the new box was much newer--I bought it from a forum member. Now I did have more SAFs on order from Swift, but it was very concerning that the new bullets shot so bad. I was kicking myself for not simply ordering a new barrel and chambering it myself. I would up talking to Bill Hober himself (a VERY nice guy). I suspected it was a slight change in bullet design, but he initially thought it was a powder lot issue, but all these loads have come from the same 8lb jug of Varget.
He then said that yeah, there has been a change several years ago. The old bullets were slightly tapered along the bearing surface, larger at the base. The new bullets were not.
I was relieved. Of course that was the issue. Bullet obturation and elongation are a huge part of accuracy. I speculated that it just wanted a little more powder, and it did. It needed a 1/2 grain more with the current design SAFs. I wound up with SAFs at 2430 fps and Swift break away solids at 2380 to have to same POI at 100 yds. In the pic, the solids are the upper left target, the other two targets are SAFs. All three groups are around an inch.
Now I just need a couple more sessions off shooting sticks and offhand, and I'll be ready. Can't wait!!
