300 PRC & 6.5 PRC Switch barrel questions

[mattbrown6.5]

I just got my Rifle completed. Originally it was gonna be a 6.5 PRC and 300 WSM. the blanks I ordered were 28" 1:7 for the .264 barrel and 26" 1:10 for the 30 cal. While waiting for the work to start Hornady graced us with the 300 PRC. I called the smith and requested he chamber the 30 cal barrel in 300 PRC. I know the 1:10 twist is a bit slow. My groups are just under moa at 100 right now with 225 ELD-m ammo. The 6.5 barrel is shooting bug holes with 147's. The 300 doesn't like my Sig 762 can. groups open up to about 2 moa. The 6.5 likes the can better than no can at all.

My Question is: What suggestions do you all have to get better performance from the 300 barrel? Will the 212 grain ammo be light enough? is the 225 ammo light enough, just need to hand load to find the sweet spot?

Second issue is mag length. I'm using Badger ordinance bottom metal. with Accutate mag 338 LM mag. It's too short for the 300 PRC with factory 225 eld-m. who makes a longer mag I can use?

Thanks for the input.

 

[NukeMMC]

My 300wm has a 26", 1:10 twist Krieger. It shoots the 208 ELDM and the 210SMK very well. That's as heavy as I have run thru it.

I run the Accurate 3.850 magazine which allows a max OAL of 3.750. The belt OD on 300wm is the same as 300PRC case OD (0.532")

 

[mattbrown6.5]

My 300wm has a 26", 1:10 twist Krieger. It shoots the 208 ELDM and the 210SMK very well. That's as heavy as I have run thru it.

I run the Accurate 3.850 magazine which allows a max OAL of 3.750. The belt OD on 300wm is the same as 300PRC case OD (0.532")

Thank you. I don't have trouble with diameter. it's the length that's too long for the 338 LM mag. My guess is the a 212 will fit fine but the 225 is just a tad too long. It's shooting the heavier bullets ok but not like I want it too. I will be loading lighter bullets for no doubt or I'll have to get a new barrel spun up with a tighter twist.

 

[MOUNTIC]

Thank you. I don't have trouble with diameter. it's the length that's too long for the 338 LM mag. My guess is the a 212 will fit fine but the 225 is just a tad too long. It's shooting the heavier bullets ok but not like I want it too. I will be loading lighter bullets for no doubt or I'll have to get a new barrel spun up with a tighter twist.

Head over to be the 300 PRC thread. Lots of good info on how the 10 twist is just fine unless your in very, very extreme conditions. Even the 300 NM has been and is fine with the 10. Dave Tooley explained it pretty well in that thread. I have a 10 and also a 9.4. I don't see any difference at all. If I did it would be in my head. Go into the Berger twist calculator and put in your info. I was more worried about spinning them too fast on my hunting rifles at elevation so I went with the 10 there. Usually shooting the 215s.