6 PRC reloading

[Titanmoose]

I’m awaiting my PBB 6 PRC barrel. Should be done in a couple weeks or so. 18” .750” taperless, 7.5 twist, diamond fluting. I had them add .040” freebore, so I’ll have a total of .180” FB.

I went with a SA (Atlas lite) so I was partially concerned that mag length / jump with above .140 would be too much for the 105-108’s. Or be hampered by OAL if you went with a tipped round.

I also know nothing so I wasn’t brave enough to add FB initially good thing barrels are cheap

 

[Runolfson]

I’m awaiting my PBB 6 PRC barrel. Should be done in a couple weeks or so. 18” .750” taperless, 7.5 twist, diamond fluting. I had them add .040” freebore, so I’ll have a total of .180” FB.

I ordered the same but in 20". What bullet are you planning to shoot? I was planning to shoot 108eldm will the standard .140fb be enough?

 

[Titanmoose]

I ordered the same but in 20". What bullet are you planning to shoot? I was planning to shoot 108eldm will the standard .140fb be enough?

I suspect it is. I don’t know for certain. You can always add FB.

 

[Schmo]

I ordered the same but in 20". What bullet are you planning to shoot? I was planning to shoot 108eldm will the standard .140fb be enough?

You’ll be fine! You might be seated .020” deeper than optimal, but realistically your velocity won’t be much difference. I don’t think it’s enough to lose any sleep over.

 

[Elk Chaser]

I went out earlier today to try out some 1x fired brass to see if I could get my SD/ES down from unfired. I'm shooting 108 Elite Hunters and had 5ea at 59, 59.5, and 60 grains N565 w/ CCI BR-2 loaded 25k off. My barrel must have sped up because velocities are significantly higher than what I had been seeing. Unfortunately my top charges didn't have the accuracy to pursuit any further. Rifle has a 20", 8 twist ACE SP3 and TBAC Ultra 5 for reference -

59gr - 3,163 avg, 18.2 ES, 7.3 SD ~1 MOA
59.5 - 3,203 avg, 20.6 ES, 7.7 SD ~1.5+ MOA
60 - 3,246 avg, 17.5 ES, 6.2 SD ~1.3 MOA - slight sticky bolt

I think I'm going to load 5 each 58.5 and 59 this weekend, pick the best of the two and just start shooting. I'm not sure if this Ace barrel isn't a big fan of these Elite Hunters or something but I may give some 108 eld-m a try at some point once I've had a chance to shoot at distance.

 

[Titanmoose]

I went out earlier today to try out some 1x fired brass to see if I could get my SD/ES down from unfired. I'm shooting 108 Elite Hunters and had 5ea at 59, 59.5, and 60 grains N565 w/ CCI BR-2 loaded 25k off. My barrel must have sped up because velocities are significantly higher than what I had been seeing. Unfortunately my top charges didn't have the accuracy to pursuit any further. Rifle has a 20", 8 twist ACE SP3 and TBAC Ultra 5 for reference -

59gr - 3,163 avg, 18.2 ES, 7.3 SD ~1 MOA
59.5 - 3,203 avg, 20.6 ES, 7.7 SD ~1.5+ MOA
60 - 3,246 avg, 17.5 ES, 6.2 SD ~1.3 MOA - slight sticky bolt

I think I'm going to load 5 each 58.5 and 59 this weekend, pick the best of the two and just start shooting. I'm not sure if this Ace barrel isn't a big fan of these Elite Hunters or something but I may give some 108 eld-m a try at some point once I've had a chance to shoot at distance.

you are right near the edge of being marginally stable according to the Berger calc depending on your altitude on your lower end speed. I don't think that is your issue but I am under 1000' so I know Ill have to step on it if I get heavier

 

[Elk Chaser]

you are right near the edge of being marginally stable according to the Berger calc depending on your altitude on your lower end speed. I don't think that is your issue but I am under 1000' so I know Ill have to step on it if I get heavier

I'm shooting at 3,500' and typically hunt 5,000-8,000'. Berger is showing 1.64 @ 3,500' & 3,150 FPS so I'm good there...I've also never reloaded for a cartridge quite this overbore and I'm wondering if maybe it's just being finicky due to that. Seeing other peoples excellent results leads me to believe it's just me though lol.

 

[Titanmoose]

I'm shooting at 3,500' and typically hunt 5,000-8,000'. Berger is showing 1.64 @ 3,500' & 3,150 FPS so I'm good there...I've also never reloaded for a cartridge quite this overbore and I'm wondering if maybe it's just being finicky due to that. Seeing other peoples excellent results leads me to believe it's just me though lol.

I have only started reloading in the last year and practiced with 6.5 cm in a 16 inch howa. so I am a ******* idiot and can offer no advice to your process LOLOL

 

[mullmann]

I am going to be reshooting 58 and 58.5 at .025 and .030 off. If that has the same results as before a friend turned the necks on a few pieces of brass for me and I am going to see if those pieces do any better. My inconsistencies are either neck tension or the necks are too thick. Still not shooting horrible, but could be better.

 

[Elk Chaser]

I am going to be reshooting 58 and 58.5 at .025 and .030 off. If that has the same results as before a friend turned the necks on a few pieces of brass for me and I am going to see if those pieces do any better. My inconsistencies are either neck tension or the necks are too thick. Still not shooting horrible, but could be better.

I think that’s where I’m at as well but I’m not going to neck turn. I’ve got the SAC die now using a .271 bushing and a .2415 expander mandrel…maybe not enough neck tension? We’ll see tomorrow, hoping this next batch I’ve got shows a little more promise.

 

[Underandoverit]

Is there anything to be had by building a 6 prc or 6 saum on a medium action? I was all geared up to build a 7 saum on a Lone Peak medium action but now I'm leaning 6mm.

 

[Elk Chaser]

Is there anything to be had by building a 6 prc or 6 saum on a medium action? I was all geared up to build a 7 saum on a Lone Peak medium action but now I'm leaning 6mm.

That’s actually exactly what I’ve got and it works great. It started as a 6.5 PRC then I downsized to 6mm and it functions perfectly.

I don’t know that it gains you anything for a 6 PRC in particular but you’ve got some more options for something larger down the road if you change things up.

 

[Underandoverit]

Thanks for the reply. Is it even possible to seat a 115 dtac or 109 eldm far enough out to require a medium action?

 

[mullmann]

I built my 25 and 6prc on a Zeus QC LA and they feed really well. Unless it’s a really short cartridge I build everything on LA. You could seat them out far enough. My 109’s are 2.92 at .030 off. 115 dtacs are longer

 

[Titanmoose]

what are people seeing for RPM's ? I have 105 HH, and 108 ELDM's with a 20" and 7.5tw 5R , and looking at some calculators, looks like the 105's could be spinning just over 300k. anyone have any experience with where you see potential jacket separation? I have heard stay at or under 300k.

Seems like with more searching people are pushing 320k these days on newer barrel/modern bullets

 

[mullmann]

berger says don’t go over 300k, but I have yet to see separation.

You also should check with each bullet manufacturer. Some people say groove count plays a part in bullets coming apart as well.

 

[Titanmoose]

MV x 720 / twist rate
MV x (12/twist rate) x60

3100 x 720 / 7.5 =297,600
3100 x 1.6 x60 =297,600

7.5” twist rate for example

I've used a calculator and done all sorts of math.

just curious where people are pushing bullets or having failures

 

[mullmann]

I've used a calculator and done all sorts of math.

just curious where people are pushing bullets or having failures

Yeah I misread and fixed it

 

[Titanmoose]

berger says don’t go over 300k, but I have yet to see separation.

You also should check with each bullet manufacturer. Some people say groove count plays a part in bullets coming apart as well.

I have heard that as well, but I have no idea. I guess Ill keep it under 320k and see what happens

 

[Elk Chaser]

Thanks for the reply. Is it even possible to seat a 115 dtac or 109 eldm far enough out to require a medium action?

In my chamber w/ appx .140 freebore a 108 elite hunter is 2.94" at .010" off the lands so it'd be close with the 115 or 109.