Lapua 7-08 vs Palma brass volume

[Mulligan]

Is there any volume difference between Lapua 7-08 brass and 308 Palma brass?
I have a 7-08AI hunting rifle and cannot get quite enough H4350 in the case a mag length to achieve decent velocity. ~2600 fps with a 150 AB is slow.....
Thanks
CW

 

[Mulligan]

@Laurie
Have you tested these two side by side?
CW

 

[Laurie]

Is there any volume difference between Lapua 7-08 brass and 308 Palma brass?

No, except the neck diameter invariably changes the 'overflow water capacity' weight reading a bit when comparing 260 / 7-08 / 308 cases.

 

[centerlineseal]

Just curious, ... I've got over 2,800 fps with H4350 and a 168 Berger VLDH in a 24" barrel in a straight 7mm-08 with Lapua brass. OAL was 2.950 ( I record OAL, but rely on CBTO measurements) Mag length must be the answer?

 

[Mulligan]

Just curious, ... I've got over 2,800 fps with H4350 and a 168 Berger VLDH in a 24" barrel in a straight 7mm-08 with Lapua brass. OAL was 2.950 ( I record OAL, but rely on CBTO measurements) Mag length must be the answer?

308 or 708 brass?

 

[Dusty Stevens]

You can either throat it out longer or go to a tad faster powder. Imr4350 is probably your answer but if you need more n150 will do it.

 

[XTR]

H4350 is notorious for rather large *British understatement* lot to lot velocity variations. I've seen loads that lost 100FPS when changing lots. I tried it in my 7-08 several yrs ago and like you found that it would not give me the velocity I was seeking.

I've got both I can check the volumes for you, but I'd look for another powder. As much as I hate to say it Varget is probably your best bet, unless this is a hunting rifle. If you're not looking for 1000 yard X-ring vertical from your loads I'd get some Power Pro 2000MR. It will give great velocity in 308 based cases. After I experimented with it in F-TR yrs ago I had a bunch left over. I run 140 class bullets from my straight 7-08 at 2900+ with loads that are rather pedestrian.

I'm sure N150 would work too, but it takes more volume, which might work out. In my 308s I can only get about 44.8 or so behind a bullet seated up into the neck before you get to compressed loads.

 

[Murray Brook]

In my 7mm/08's I've gotten great accuracy and velocity with 140/150 gr bullets with WW760/H414.

 

[Laurie]

Swedish manufactured (Bofors) powders Norma URP and Alliant Re16 may be the way forward on higher 7-08 MVs. (Both have only recently become available in the UK, yet to try them.)

I run necked-down / turned 308 Palma cases in my primary combination, but with the powder I use (Viht N160) I'd almost certainly get higher MVs in large primer Lapua brass and even more so, higher capacity Winchester.

I reformed and neck-turned 100 Palma 308s as:

1) I had lots on hand spare after my F/TR shooting days finished.
2) MV consistency
3) case life as my experience is that moderately warm loads in the 260 / 7-08 / 308 family have a 5 or 6 firings life before primer pockets loosen. Annealing the reformed small primer cases every 3 or 4 firings may give a near indefinite life, the barrel shot out before the brass. (At which point, the rifle becomes 6.5X55 as I have a low-round count Bartlein barrel so chambered / threaded for the action, it having been cannibalised for a 308 Win F/TR build some years ago and the barrel stored for a later date.)

 

[centerlineseal]

308 or 708 brass?

7mm-08 brass

 

[Mulligan]

I have tried RL-16, RL-23, H4831, and H4350.
All are too bulky for the case capacity. It is a hunting rig.
I will try VarGet and/or H4895.
@Dusty Stevens I have never used N150, if I find some locally I my give it a go.

I was kinda hoping the 308 Lapua brass had a touch more capacity than their 708 brass does?????
CW

 

[Dusty Stevens]

According to how much more you need over h4350, imr4350 is a touch faster

 

[centerlineseal]

I started with IMR4350 in working up some loads for my 700 VLS. 140 NBTs, 150 Nosler Solid Base and 160 NBTs. All shot about 1 MOA in the range of 44.0 to 46.0 grs over Fed 215s, mixed brass. Not near as accurate as I wanted. No chrono data from my notes.

In my son's Tikka with a 22" barrel with 160 gr Nosler Partition, Sammi length @ 2.800, ... 44.0 gr IMR4350 over a BR-2, 2,450 fps and 3/4 MOA (Lapua brass). Found a powder node for a 160 NBT @ 45 gr.

Next is to work up a load for 140 gr and/or 150 gr Nosler Partition for that Tikka with H4350, as we seem to get better accuracy. Shoots well with 140gr Berger VLDs @ 47.2 gr H4350. 3 shots into 0.612. No chrony data in that rifle.

In the VLS with 140gr Berger VLDs @ 47.2 gr H4350, 5 shots around 3/4 MOA, 2,862 fps with 7.9 SD for 5 shots. Seating depth adjustment should tighten that group.

hope this helps.

 

[wolfman]

if it’s a hunting rifle, Rl15 should get you where you want to be.