What's your seating depth off the lands on the Berger 300g Hybrid OTM?

[jmden]

What's your seating depth off the lands on the Berger 300g Hybrid OTM for best accuracy? I know there are a number of variables involved as to why a certain combination of components may result in a certain seating depth for best accuracy. I'm just wondering if there seems to be a consensus on a general 'sweet spot' or not. I know some have found it to be fairly insensitive to seating depth but am hoping to hear from all of you that are using it to see if there is a trend or not. Thanks for the input.

 

[Broz]

300 yard accuracy was .5 moa with all depths from .015" off the lands to .060" off. .015" had a slightly better ES so I went with it.

Jeff

 

[jmden]

300 yard accuracy was .5 moa with all depths from .015" off the lands to .060" off. .015" had a slightly better ES so I went with it.

Jeff

Jeff, Did you try nudging a little closer to the lands? If so, what happened?

 

[Broz]

Jeff, Did you try nudging a little closer to the lands? If so, what happened?

No I did not. I was staying back if I could find accuracy there, to keep the pressure spike down.

Jeff

 

[AZShooter]

I seated the 300 OTM into the rifling .010". I had ample room in the LA for the long throated 338 RCM.

Since then I have worked up loads for the following hybrids with a jump to the rifling. All were random with OAL determined by magazine length. Only one required tweaking of the seating depth, the 284 win which liked a .025" jump.

6mm 105 in a 6mm-284
7mm 168 classic in a 284 win
308 168 target in a 300 RUM
230 target in a 300 RUM
230 target in a 300 WSM

I suggest you simply choose a seating depth and work up a powder charge. That may be all you will have to do.

 

[Broz]

I suggest you simply choose a seating depth and work up a powder charge. That may be all you will have to do.

Plus 1

.

 

[royinidaho]

I've jammed that bullet so hard into the rifling that if I didn't fire it I had to use a rod to get it out. Accuracy was out standing with 101.5 gr 50 BMG. Was great for rock bustin' but not nifty for actual hunting. Backed it in just enough to get unfired extraction. Accuracy, velocity and low ES is still there.

 

[jmden]

I've jammed that bullet so hard into the rifling that if I didn't fire it I had to use a rod to get it out. Accuracy was out standing with 101.5 gr 50 BMG. Was great for rock bustin' but not nifty for actual hunting. Backed it in just enough to get unfired extraction. Accuracy, velocity and low ES is still there.

Interesting...what chambering and what MV, Roy?

 

[royinidaho]

Interesting...what chambering and what MV, Roy?

Factory Rem Sporter 26 inch 338 RUM;. MV = 2735 +/- 1 (usually, so far, most times, etc) Me thinks RL-50 will get a little more. Gonna try, one of these days.

 

[jmden]

Factory Rem Sporter 26 inch 338 RUM;. MV = 2735 +/- 1 (usually, so far, most times, etc) Me thinks RL-50 will get a little more. Gonna try, one of these days.

I shoulda realized that was the rifle you were talking about. You had very good ES in that rifle with 300 SMK's as well, didn't you?

 

[royinidaho]

I shoulda realized that was the rifle you were talking about. You had very good ES in that rifle with 300 SMK's as well, didn't you?

Yep . . . the bergers produce a smidgen smaller groups. Not much but enough to measure.

 

[SidTheKidd]

Seating my 300 OTMs .010 off the lands with my 338 Norma. Shooting 92 grains Retumbo with CCI 250s @ 2750fps. Holding .5 MOA.