I ordered my Berger 195s on Thursday they got here yesterday(I live 25 miles away). Started on some measurements. I have a long throated 28Nosler(1 in 8) built on a Win 70 RUM action. At max mag length of 3.65" my measurement to ogive was 2.88 - exactly what the measurement to ogive was for the Nosler 175ABLR when it was maxed out 3.56"; leaving the bottom bearing even with the bottom of the neck. The Berger 180s are pretty close to the same as the ABLR with a little longer OAL. I could install a Wyatts box and extend the 195s to almost 3.8" but everything else would have to jump a ways. Not worried about the ABLRs because I've had to jump them .05 to .1 in everything else to get them shooting well. Would you shoot as is or add the Wyatts? The smith will throat to what ever spec I give him.
28 Nosler and 195gr Bergers
- Thread starter muleman
- Start date
NWBlacktail
Handloader
- Dec 17, 2011
- 357
- 0
That's a bran new bullet, and obviously very interesting. But the 175 ABLR and 180 Berger would probably be what I'd chamber for, but still give the 195 a try.
Don't you need like a 1:8.5, or 1:8 twist? Maybe with the 28 Nos you can push it fast enough to get away with the 1:9???
Don't you need like a 1:8.5, or 1:8 twist? Maybe with the 28 Nos you can push it fast enough to get away with the 1:9???
The boattail length on most big Bergers is .250" so if you do a little math I come up about 3.67 as optimal. 1.62" bullet length - .25" boattail length - .290" (roughly the neck length) = 1.08" sticking out of the case. That plus the case length of 2.59" = 3.67". If it functions through your magazine at 3.65" that is where I'd throat it. .020" plus your jump amount below the neck shoulder junction won't kill you or you could always throat it for 3.65" plus .010" jump.
I've got it better than you though since my cases will only be 2.5" long. The down side is I'll need a Wyatt mag box for the 338 Norma Imp case I'm necking down for it. In my 30-338 Norma Imp with 230 Bergers and a .235" throat my OAL is 3.608". The 230's are basically identical to the measurements I've seen for the 195's. Length, bearing surface, boattail, etc. I will probably throat it close to the same as my .30 since it works for 215's and 230's as a in between throat length. That puts about .020" below the neck shoulder junction with 230's.
I've got it better than you though since my cases will only be 2.5" long. The down side is I'll need a Wyatt mag box for the 338 Norma Imp case I'm necking down for it. In my 30-338 Norma Imp with 230 Bergers and a .235" throat my OAL is 3.608". The 230's are basically identical to the measurements I've seen for the 195's. Length, bearing surface, boattail, etc. I will probably throat it close to the same as my .30 since it works for 215's and 230's as a in between throat length. That puts about .020" below the neck shoulder junction with 230's.
Guy Miner
Master Loader
- Apr 6, 2006
- 17,858
- 6,417
How much of a twist rate is needed to stabilize a 195 grain, 7mm bullet? That's got to be one long son-of-a-gun...
Worse case Berger recommends a 8.3 twist. If you run the numbers through their twist rate calculator I can shoot them in my 9 twist at my elevation (2800' where I shoot) in all but the coldest temps but I bet they are still stable. They may not be at the optimal BC. At sea level and freezing temp you need a lot more twist and that is where the 8.3 twist came from. I have Kreiger 8 twist for my new toy although a 9 twist would probably be fine for me since just about everything I do requires gaining 2000'+ of elevation.
I don't have mine in hand yet but from measurements I got from others they are almost identical to a 230gr .30 cal. Berger just in 7mm.
I don't have mine in hand yet but from measurements I got from others they are almost identical to a 230gr .30 cal. Berger just in 7mm.
- Thread starter
- #7
My actual measurements are .2" boat tail, .665" bearing and 1.615 "total length. My math gets me only a .08" bearing impingement into the case if I stay at a COAL of 3.65". Not bad, not enough gain to go with the Wyatt's box. I'm running a 1in8 twist Benchmark at 26". I live at 473" above sea level and do my load work at 2200'. I went with the 8 twist because I'd been hearing about the 195gr Berger for a couple of years and I'd rather over stabilize than under stabilize. I've got 5lbs of RL33 and 3lbs each of H1000, Retumbo and US869. A couple hundred each of 195gr, 180gr Bergers, 175gr and 168gr ABLRS and a case of Fed 215s. Gonna burn some powder!
Scott
Scott
I got mine today and measured them. I got at .220" boattail length and 1.624 OAL on the one I measured. I wouldn't worry about being .080" in the case. I run my Edge more than that and it's stupid accurate.
The bearing surface is almost the same as the 230 30 caliber but the boattail is .250" on the 230 and the OAL is 1.668". I'm pretty sure I can get 3150-3200fps out of the 195's in a 28" barrel when I get my 7-338 Norma Imp done and 3000-3050 out of my 7-300wm.
The bearing surface is almost the same as the 230 30 caliber but the boattail is .250" on the 230 and the OAL is 1.668". I'm pretty sure I can get 3150-3200fps out of the 195's in a 28" barrel when I get my 7-338 Norma Imp done and 3000-3050 out of my 7-300wm.
- Thread starter
- #9
IdahoCTD":1exhebyr said:
I'm thinking I'll be right between those two with the long 28Nosler in a 26" 3050 to 3100 with the 195s and 3150 to 3200 with 175/180s. At least that's Q/L is predicting. Now that the 195s have been released I might leave the barrel a little longer.
Guy Miner
Master Loader
- Apr 6, 2006
- 17,858
- 6,417
"Free" velocity with that longer barrel. Well, kind of free.
Guy
Guy
muleman":x5xapvvo said:
I bet your about right. My 30-338 Norma Imp is 108.6grs of water with 423 Dakota cases and I'd expect over 108gr in 7mm. It's pretty much a 7RUM with better Lapua made brass and only 2.5" long cases. So you can load it hot and the brass will last 15+ firings. The brass is a pain to form but it only cost me 35 to 50 cents a piece. 50 rounds will wear a barrel out. Now that I have bullets I can send a case out with the print and get a reamer made.
