308 win and the berger 215

[MontanaMarine]

Canadian Bushman,

I'd definitely go 1/10 twist for the heavies. Also for the 215 Berger, I'd throat for about 3.10" oal. That leaves abour .315" of bearing surface in the case neck, or just about to the neck/shoulder juncture.

Yes I made 2600 fps with 215s, in a 26" bbl, with RL17, moly, and a 3.10" oal.

Details here:

http://www.longrangehunting.com/forums/f19/215gr-berger-hybrid-308win-104197/

I had a small number of bullets and didn't get past the 100 yard line in my limited test.

But, I've had good results with the following in a 1/12 20.5" 308, all shot out to past 1000 yards, even some crazy plinking out to a mile+,

208 AMax
210 Berger
215 Berger
220 SMK
225 Hdy BTHP.

All the above I moly'd, loaded to 2.9-3.1" oal in Win brass, and charged with 48-50 gr of RL17. Velocities ranged from 2500-2620 fps.

I'm only using the 1/12 barrel as it is the factory tube, 1/10 would be mt choice if going custom.

Shane

 

[minute of elk]

I copied montanamarine's loads- minus the moly- in my 11 twist Tikka & have been pretty darned happy with it. This load shoots .4-.7 moa & has given me consistent hits out to 1000 yards.
48.5 grains of R-17 in CBC brass (it was free!), 3.004" COAL, br2 primers, 208 Amax, 2640 fps with extremely low es

I'm not sure what the difference in bearing surface is between the Amax & the 215, but I'd love to try em out! Long seating heavies in the tikka is like cheating- modify the bolt stop, buy a long mag, and run em as long as you dare. I don't know if I'd be as wild about them if I had to single feed, though...

 

[MontanaMarine]

Your Tikka is a real sweet rig!

You were beating up the 1000 yard steel in Townsend!

 

[Canadian Bushman]

Shane,

Your results have convinced me to re barrel the 308 for the 215 hybrid. I think if i can keep it faster than 2500 fps i will have a good 1k gun. Something i thought the 308 just couldnt be.

What should i use for a starting load?

How big of a contributing factor do you think the moly is?

 

[MontanaMarine]

You'll have no trouble getting over 2500 fps, especially with a 28" bbl.

Starting load of 44gr RL17 should be very safe. I'd work up in .5gr increments.

Moly definitely reduces friction/pressure, so it does allow a bit more powder/velocity. At the end of the day, it's probably going to gain you 30-50 fps in the 308/215 combo.

There are so many variables in chamber/throat/bore.brass, etc that it's hard to know where you will end up.

My 49 gr load seemed fine in my rifle, but keep in mind mine is a factory Remington with a very long throat, 3.10" oal was still off the lands about 10/1000". Also Win brass is about the highest volume 308 brass out there, and moly reducing friction. Basically I have a few different variables stacked in my favor regarding safe charge and velocity potential. Another rifle/brass combo might top out at 46-47 gr. You just don't know till you work with it.

Shane

 

[Canadian Bushman]

Shane

Thanks a lot. I really appreciate the input. Im gonna try and get a barrel on its way.
Ill talk to the guys at lilja and see what they recommend for a throat length, because i dont want to get it too far out there and have trouble reaching the lands with a lighter bullet if i decide to go that way.

How did you find the recoil of the 215's or even the 208 amaxs to be?
Also do you have any info on temp sensitivity of re 17?

 

[MontanaMarine]

Something to consider when you spec your throat is that if it's shorter, you will have to seat the heavies further and reduce your useable case volume.

Recoil, well I've got brakes on my 308s. I've shot them without, and recoil increase over a 155 Scenar is significant. It's no 300 RUM or even close, but a noticeable increase for sure.

RL17 is fairly temp sensitive in my experience. I lost about 30-40 fps from 80F to 40F...roughly 1 fps per degree. Haven't chrono'd down around zero or lower.

 

[Canadian Bushman]

Didnt get to phone lilja today. If i ask the gunsmith for a factory rem throat length will they know what i want? I dont know the actual number for the amount of freebore i have now or what i would need for the 215.

When you seated the 215 to 3.1", was 49gn a compressed load?
How far were the 215s jumping/jammed?

My gun is pretty heavy, i think i could tolerate a little more recoil. If it ends up being uncomfortable i can always build a brake for it. Ive been wanting to try that.

1fps/deg isnt that bad. I think i have .7 for imr 4064 but its hard to say. Sometimes that temp/vel ratio doesnt seem linear. Especially in texas summer.

 

[MontanaMarine]

I couldn't tell you what a gunsmith would or wouldn't know. If it were me, I'd include an inert dummy round with the bullet of choice seated to the desired oal, and ask the smith to throat accordingly. I'd ask for the bullet to be 10 thou' off the lands.

Another thing to consider is this. If the oal is too long, you may not be able to eject a loaded round without releasing the bolt stop. In my Rem's, 3.08" is about it in factory form. I had Wyatt's long mag boxes installed, and the boltstops shortened accordingly. That bought a little more oal latitude with ability to have a loaded round clear the front receiver on extraction/ejection.

 

[Canadian Bushman]

I think i will get some 215s and re17 to experiment with so i can send a dummy when its time to chamber the barrel. I measured my throat at about 2.325" last night i think saami spec is 2.302. This will tell me more after i get some 215s.

Another thing to consider is this. If the oal is too long, you may not be able to eject a loaded round without releasing the bolt stop. In my Rem's, 3.08" is about it in factory form. I had Wyatt's long mag boxes installed, and the boltstops shortened accordingly. That bought a little more oal latitude with ability to have a loaded round clear the front receiver on extraction/ejection.

I have not considered this. Definitely something to think about. I know i can still eject my 185's at an oal of 3.05 but not sure how much further i can go.

When you seated the 215 to 3.1", was 49gn a compressed load?

 

[MontanaMarine]

There was light compression with 49gr, and 215 at 3.10" oal. Not enough to mark the bullet tip with the seater.

 

[Canadian Bushman]

Thanks a lot Shane.
I know a whole lot more about what i want to do than i did a week ago.

 

[MontanaMarine]

I have to take back what i said about the 215 not being marked on seating over 49gr RL17 at 3.10".

I went back and looked at the pic of the round in the linked 215 thread, and there is a slight but visible mark on the bullet from the seater. Compression didn't seem heavy though, as I recall.

One thing about using moly'd bullets is that if compression is heavy, the oal will 'grow' due to the reduced friction between the bullet and case. I didn't have any of that with the 215s over 49gr. That was in fireformed and neck-sized Win brass.

 

[Canadian Bushman]

I know its hard to say with so many unknowns at this point, but could we assume that 3.100" is close to if not minimum COAL to be used for optimal velocity, and charge weight. ?