Years ago I had a tanfaglio witness in 10mm. Loved the look but didn’t love the pistol, long story short, I sold it 3 years ago and have been on the prowl for a replacement. A few weeks ago, I ended up getting a Glock G40 with trijicon RMR.
I had 1 box of Remington factory 180gr FMJ and about 50 old reloads with 180gr Berry’s HP, loaded with light charges of HS-6, AA7, and power pistol. These all shot pretty well out of the witness. The factory ammo shot incredibly out of the Glock, but the old reloads all keyholed, not a single one hit the target nose first. I figured that this was happening because of the Glock’s 9.5” twist, as opposed to the standard 16” twist.
I made up some super light (medium 40S&W) loads with Bullseye and W231 to see if that would get those Berry’s shooting straight. They didn’t keyhole but they shot about 15” groups at 15yds. Back to the drawing board. I need to get these to shoot because I have 140 of them left at this point, and they need to disappear.
I also have a box of 1000 Rainier 165gr HP (were supposed to be 180’s but they shipped the wrong ones) left over from many years ago. Fearing the same problem I was having with the Berry’s, I set out looking at 40S&W data again. I found some data using auto-comp and I just happened to have a brand new pound of it from when it first came out. I loaded up 10 of the Rainier 165’s with 6.0gr of Auto comp, lo and behold, they shot an inch group at 15yds. I was so excited that I ran home and loaded up 10 of the Berry 180’s with 5.5gr of auto comp. I went back to the range this past weekend, set up my chronograph and gave it hell. The 165 Rainier load shot very well again and averaged 950fps, and the 180 Berry load shot a 2” group with perfectly round holes, it averaged 930fps. Good enough for me.
Now I can use up the last of those Berry’s and all of those Rainier’s. When they are all gone I’ve got 1000 Xtreme 180gr HP to focus on. I’m hoping to get a practice load with them using a more traditional 10mm powder, going about 1100fps.
JTD