6.5x47L Owners

[mullen7]

Afternoon,

I'm looking for some advice, about to start my journey into the custom rifle builds and I'm just gathering the last few pieces of my build.

I've been asked what throating I want, now I plan to shoot 123gn up to 140gn heads, so I know I need to get a 1:8 Twist, that is no bother, however what I'm not sure, is whether to throat for 123s, and then seat the bigger heads deeper, or go for 140gn throating, and use 123s.

Does anyone have any experience on this? I know theres a few gunsmiths on here which will certainly help me out, or at least I hope. And also I know Laurie may have some advice, so hoping he sees this and pops up.

Any advice at all is muchly appreciated.

Blair

[mag41uk]

The problem is that no two 140gn bullets will have the same profile.

[Laurie]

Most gunsmiths chamber 6.5X47 builds with a relatively short freebore that gives around 2.650" COAL with the 123gn Scenar and equivalents. That suits 120-130gn bullets but is a bit short for the longer 140s. (Those COALs are 0.145-inch shy of the CIP nominal 2.795" value.) The heavier (136-142gn) bullets can still be loaded OK, but are seated a bit on the deep side. This will reduce available MVs a little, the exact amount depending on the powder used, actually very little with 'high-energy' types such as Viht N500 series and Reload Swiss RS52 and RS60.

If you're having a dedicated long-range competition rifle built where you're looking to load high BC 140gn class models to optimal available MVs, a longer throat is better, but there is some anecdotal evidence around that barrels so chambered don't do as well with the 123s. I have an acquaintance who was given a 'short freebore' chamber by his gunsmith, and when he found he couldn't seat bullets at the near 2.8" level played merry hell with the rifle builder eventually getting it 'throated out'. He later told me it was a poor decision and when he shot that barrel out went for the more common shorter freebore in its successor which he's found works better.

The better 123s and 130s really do perform well in this cartridge out to surprising distances, and it's only really at 1,000 yards that you start to feel they're a bit lacking against equivalently aerodynamic 140s. As an example, I used my old 6.5X47 BR / F-Class rifle in the 2014 F-Class European Championship meeting at Bisley which kicks off with a 2+15 at 800 yards on both days of individual comps. Despite barrel issues that saw excessive coppering as the round-count went up throughout the day affecting 'elevations', I shot possibles with the 123gn Scenar at just under 3,000 fps at that distance on both mornings. (Not that did me much much good as my V-counts were 7 and 8 thanks to elevation variances and that was only good enough for IIRC 28th and 32nd (out of around 100 competitors) in F-Open such were the number of 'possibles' shot in the relatively 'quiet' early morning conditions. Apart from a few points lost due to the 'funny elevations', it actually did quite well too in the final 2+20 1,000 yard match, my score equalling that of my partner Steve Thornton, a member of the GB FTR team shooting very hot 308 loads in the FTR class, and that despite a 6 o'clock '3' coming out of nowhere early in the match thanks to the coppered-up barrel.

The other thing to consider is that if you start out with a long freebore, you're stuck with it, short of having the barrel removed, set-back and rechambered / threaded, whilst extending the freebore is a simple job for the gunsmith using a hand reamer with the barrel in situ.

I never had much luck with 130s in my 6.5X47L barrel, neither the Berger VLD nor Norma equivalent performing for me. However, we should see the new shorter but still very high BC Berger 130gn AR-Hybrid Tactical arrive here soon. It really benefits the COAL-constrained 260 Rem most, but should also make shorter freebore 6.5X47Ls more competitive at very long ranges too.

http://www.bergerbullets.com/new-65-130 ... -tactical/

With a G7 0.920 'form factor' value, it really is an impressively efficient design. (That is, it generates 8% less drag on average than the efficient G7 'reference projectile'.)

[mullen7]

Laurie, once again your knowledge of this calibre impresses me. Thanks very much you've made my decision a lot easier. I will go for the shorter freebore, leaving me having to seat the heavier rounds a little deeper. You sir, are a star. Thanks a bunch.

[WelshShooter]

I'm afraid I can't really add more value than Laurie has already given!!

My rifle is throated such that 123gr Lapua Scenar's at COAL of 2.663" are touching the lands. I've exclusively shot 123gr Lapua Scenar's and 123gr Hornady A-Max bullets through my rifle with a muzzle velocity around 2,950fps. For me, these projectiles do the job quite well. I was thinking about trying some 139gr Lapua Scenar's a month ago but the maths didn't add up.I did some ballistic charts for 123gr Lapua Scenar's and 139gr Lapua Scenar's and based on a small amount of 90 degree wind at 1,000m there didn't seem much benefit in using 139gr Lapua Scenar's for combating the wind. I'm shooting at Fig11 targets whereas I guess you'd like as much improvement as is possible for F-class so it might be beneficial for you.

[mullen7]

Well that's my predicament Welsh, I'm shooting currently at 200 and 500, will be shooting F-Class but will be taking it out to 1000 for sure, even just to stretch its legs if not compete. I think I'm going to end up just going for the shorter freebore, as I will use 123s mainly, and then seat the larger bullets a little deeper. At the end of the day, the barrel is a renewable part, albeit expensive to a degree, if what I plan doesn't work, next barrel I can change it up or just get it re-barrelled, at the end of the day it's a learning curve that I need to take.

[The Gun Pimp]

My freebore is 0.110 in. That's perfect for the 120/123 gn Scenar. These bullet-weights are good enough for 1000 yd 'club' F Class.

[shotgun sam]

Hi Blair,
When are getting the new toy?

Sam

[mullen7]

Ordering this weekend Sam, just waiting on Joe west getting back to me regarding a stock.


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