308 in F-Open

[Winston]

G'day Gurus,

First post here, so please go easy...

I've only been shooting for a couple of years (f-class since day one though) and I'm in the process of building a new f-open rifle that I intend to run as a switch barrel (6x47l for up to 500 or 600 and something much bigger and slipperier for the longer ranges). With the absolutely shite availability of projectiles at the moment, I'm making sure I build something I can actually find lead to feed.

I've spend a gut load of time playing with Quickload, using Litz's Applied Ballistics app and reading and have stumbled onto an odd potential choice for f-open - a 308w firing 230gr Berger Hybrids.

Why this looks good (particularly in comparison to a 284 with 180's which would be my other choice)

a)With a MV just shy of 2500 fps (lining up with an OBT node for a 30" barrel), the 1000 yard drift figures are on par with what a 284 will do with a 180 vld

b)Recoil energy calculates at 9 ft/lbs vs the 8.5ft/lbs the 284/180vld combo produces

c)I have a good supply of 230's, and Redding type S dies

d) Quality 308 brass that needs no prep is everywhere (can't say the same about 284)


Why this looks bad

a)I've never heard of such a combo being run in open (f/tr guys do but aren't super keen on the combo it seems as they get beaten around with their lighter weight limit)

230gr seems like an awfully big pill to throw from the humble 308, but proportionally it's nearly identical to 90gr in a 223.

So what am I missing? Is it just that the boring 308 has been passed over for short and fat new stuff, or something else?


Cheers Fellas

[AlanF]

Winston,

I think it would be interesting to try. One or two F/TR shooter have used 230s with some success even with a 8.25 Kg rifle, although I don't know of anyone currently doing it. Not sure about the 2500 fps with 230s - to maximise your velocity without excessive pressure, I'd recommend a very long barrel, say 34", and the slowest powder that will do it for you. And you might want to consider doing a 308 Ackley improved, i.e. steepen the shoulder and reduce the body taper a little. This is one of the attractions of F-Open - the rules allow you to be different and try out your own theories.

Welcome to the forum.

Alan

[Old Trev-39]

Hi Winston,
An alternative for some thought for your new "F" Class could be the 6.5 x 55 Rogue. Good Lapua brass available as with 139gr.Lapua Skennar projs. in front of 46.8gr. 2209giving 2870 out of 29 " barrel is accurate and easy to shoot. This is what I am using and my rifle weighs in at 9.95kg. This calibre has been used by a few Nth.Qld. shooters for some time with excellent results. Pacific Tool and Die have this reamer as a standard product. This would save you having two barrels and loading dies. I bought two blank die bodies from Nulon Engineering in U.S.A. and used the chamber reamer to cut them, works well.
Trevor.

[RDavies]

A 10kg 308 shooting 230s is something I have been keen to try for a while now. Like you say, it has similar ballistics to a 284 but I suspect it might be slightly more critical of hold and rest set up due to a heavy slow bullet having more momentum and barrel time. The good side is that barrel life should be better than a 284 and MAYBE less elevation shifts on ranges with big mounds and gullies between the mound and target. (I stand to be corrected on this by those know otherwise).

[Longranger]

I've seen Mark Fairbairn give the F Open guys more than a run for there money using an F-TR rig....

No doubt you could have a good hit with it. I suspect the apogee of the trajectory would be higher but how much of a disadvantage that would be I do not know. It may even be an advantage under certain conditions with less turbulent air.

Those 230 grain pills would have considerable inertia so should be able to punch through the dirty air with aplomb. Recoil should be more manageable in an F Open rifle too. With 10kg's vs. 8.25kg's with an F-TR rifle, the extra weight would help soak up the recoil.

Sounds like it could be an interesting project.

[DaveMc]

I have actually built a 308 F open rifle for myself in last few months. I originally went for the 215s due to the work here and in Brisbane of a few guys trialling many combinations. I wanted to take it to a Queens (was originally going to be NQRAA but didn't get it worked out in time).

The 308/ 215 combo works extremely well. Is effectively on a Par with the 284 with regards wind drift, very similar behaviour in the bags etc etc. There seems to be a lovely wide node and in Qld it is not really worth taking the 30 cal to a much bigger case.

Of course availability of 215's is now very low. Due obviously to their popularity and ease of tuning. Quite a few have tried with the 230 with only moderate success - There is still a possibility it could be very good - we need a few more people to try.

So with similar wind drift, similar recoil etc the 215/230 308 should also yield a much greater barrel life and early indications are the same. Looks like a great all round work horse for F open.

[Winston]

Thanks for the replies Fellas. Looks like the numbers stack up, so I'm going to take the plunge.

Now any suggestions as to where a man might get a quality 1:9 twist 30 cal barrel without having to wait for one to be made?

I've used Total Solutions Engineering in the past and have been largely happy with the results and they did a solid job of looking after me after sending a barrel I wasn't happy with (they supplied and fitted a replacement for free). With that said, you don't hear them mentioned much in competitive circles and their turnaround time hasn't been great.

Excited to get this going. I'll post my journey along the way.

[Quick]

Funny this post should come up as I've been thinking of doing a 308 with 185gr for the shorts to save my 7mm08AI for the longs. Very interesting thread. Cheers.

[Ray Hurley]

Hi guys
I have a 30cal up and running which shoots 185s and 215s very well.the issue I found is it is testing the friendship with the 308 small primer case.its fine for 185 but as you get to the bigger pills the cases suffer.great rig to shoot and another advantage is it swaps between my f open stock and my ftr stock and is great in both divisions.
happy shooting
Ray

[Winston]

G'day Ray,

Are you saying that the cases can't handle the pressure of the bigger loads or that the small rifle primer isn't adequate to light the charge?

Cheers,
Alex

[ShaneG]

Give Craig McGowan a call - he has good stocks of Bartlein and Krieger now?