155's in 10 twist for FTR

[CZ550]

I have a 10 twist Brux on order for my new FTR rig and was planning to run the 185-200's but I have ended up with large supply of 155's. I will shoot 600 90% of the time I am thinking maybe it would be best to throat the barrel for the 155's.

Am I hadicapping myself by not running a 12 twist for the lighter bullets vs the 10 twist.

 

[NateG]

I'm running the same throat (a short one, too: the 2011 fullbore reamer) for 155 and 200 grain berger hybrids, and it works well for both. But, I could probably get the 200s going a bit faster with a proper throat for them. I shoot prone, so it's less of an issue than F/TR when you're desperately trying to claw your way into that itty bitty 10 ring. A slightly longer throat would probably be a better compromise, for what it's worth.

As to the twist, a 10 will be fine. I think there's an old article here somewhere about Whidden winning the Palma trials (in 2007, perhaps?) with a 10-twist and the required 155s.

 

[XTR]

My personal experience with a 1:10 and 155s was less than ideal, but I read a lot of posts from people who had success.

Shoot them and see. The problem may be your choice of chamber throating, the ideal throat for a 155 is not the same as the ideal throat for a 185. I'm pretty sure that I can't reach the lands with a 155 holding in the brass. You kind of need to decide what you're going to shoot before you chamber it.

 

[CZ550]

I will have the throat cut for the 155's so seating depth wont be an issue. Just wonder about using the 10 twist vs 12 for the 155's.

 

[Laurie]

Unless you're planning on shooting the 185 and 200gn Hybrids - which are really long bullets - you can normally get a compromise chamber that'll work well with most 155s seated shallow in the case, the 175 and 185gn Berger BTLRs seated near optimally, and 210 VLDs plus the Berger BTLR seated a little on the deep side.

We found this out by accident specifying a freebore figure to Dave Kiff at PT&G based on the long-for-weight 155gn Lapua Scenar seated optimally and intended for a slow-twist barrel. When the 185gn Berger appeared, the chamber was near ideal for it too.

My second 308 F/TR rifle barrel was a heavy 1-10" twist 30" Broughton, used this chamber too and would give the 185gn Berger BTLR ~2,825 fps over Viht N550 in Lapua brass with very small groups and superb elevation consistency at 800-1K. I also successfully used it with the 155gn Scenar, Berger VLD, Dyer HBC VLD, and 155.5gn Berger BT Fullbore in shorter range matches over N150 at ~2,950 fps and it shot the two 210gn Bergers and 208gn Hornady A-Max very well too using small primer Lapua 'Palma' brass and Reloder 17. It was a little short-throated for the last named trio but still produced ~2,575 fps with 17. It really was a great all-round combination and I loved it. Sadly, the N550 and Re17 loads beat it to death at around the 2,300 round mark.

The 1-10" twist worked fine with everything - it'd produce sub quarter-MOA groups with the 155.5gn Berger off the bench at 100 yards and small ES values with N150. I had some excellent match results at 300-600 yards with the 155gn Australian Dyer HBC VLD over the same powder (much cheaper bullet in the UK than the 155.5gn Berger).

 

[mao0720]

On the rifle Im having built now, the reamer being used is set up for mag length FGMM factory ammo to be .01 from the lands and should be close to that perfect all around chamber that Laurie described above. Im going with a 1-11 twist though.

 

[XTR]

On the rifle Im having built now, the reamer being used is set up for mag length FGMM factory ammo to be .01 from the lands and should be close to that perfect all around chamber that Laurie described above. Im going with a 1-11 twist though.

If you are really going to shoot FGMMs you have a hella lot of confidence in the consistency of seating depth from the factory, I won't even try to create my own loads in any serious quantity that are closer than -.05 or at least +.03. I made that mistake early on in my shooting and got some pretty big vertical swings at 1000. The problem is that you'll have one in the lands and the next out and the resulting difference in pressures causes differences in MV. In general I either seat at least .010 out or .05 in and I get consistent inside of .75MOA and closer to 0.5 MOA at 1000.

 

[mao0720]

Im not shooting FGMM, thats just waht the reamer was based off of. I plan on shooting 155 gr SMK palmas, but I liked the idea of being able to use the heavier bullets too. Im just saying that the throat length should be about ideal for using use a wide range of bullets well.

 

[mshelton]

Yeah, those 155s won't work for you, just send them my way 8)

 

[mao0720]

Close...

 

[Budget]

If you are really going to shoot FGMMs you have a hella lot of confidence in the consistency of seating depth from the factory, I won't even try to create my own loads in any serious quantity that are closer than -.05 or at least +.03. I made that mistake early on in my shooting and got some pretty big vertical swings at 1000. The problem is that you'll have one in the lands and the next out and the resulting difference in pressures causes differences in MV. In general I either seat at least .010 out or .05 in and I get consistent inside of .75MOA and closer to 0.5 MOA at 1000.

Hi there can you please help me out with speed? I’m a Palma shooter from Australia and want to shot 155 lapua scenar L out to 1000 @ 2980-3020 area.

 

[Martin52]

A 12 yo thread but no matter - I recently tested Lapua 155 Scenar L's in my 10T 32 inch FTR rig to potentially use at shorter distances instead of the 185 Jugg's or 200.20x's I normally use.

In Palma brass with Fed 205M primers, 46.3 gr Varget/AR2208 with COAL 2.860 I was only getting ~ 2970 fps, so the lower end of the range you are looking for. Vertical was very good, horizontal not so good but ok, it was little gusty.

 

[ChrisNZ]

..I had some excellent match results at 300-600 yards with the 155gn Australian Dyer HBC VLD ...

A real shame they are no more.

The machinery for making them is apparently still "somewhere" but nothing has been resurrected yet.

 

[XTR]

Hi there can you please help me out with speed? I’m a Palma shooter from Australia and want to shot 155 lapua scenar L out to 1000 @ 2980-3020 area.

Serious thread resurrection here.

I have no experience with the Lapua 155s. Personally never shot 155s much at all. You’ll need to get some of the Palma shooters to chime in.

 

[Fire Dog]

Hi there can you please help me out with speed? I’m a Palma shooter from Australia and want to shot 155 lapua scenar L out to 1000 @ 2980-3020 area.

Are you shooting at Belmore or Canberra ?
I have Peterson “Palmer” brass that performed extremely well but needed a faster powder and a magnum primer to get all the powder burnt. {44gr AR2206/H4895 +CCI 450}
The AR2208/Varget just wasn’t getting all burnt and “Fire Balling” out front of the muzzle…
Didn’t own a chronograph at the time but I was putting five 168’s into nearly one hole at 100mt.
Defiantly a “stiff” load but no bolt lift problems or pressure sign. {this is of course valid for MY rifle.. Always use someone else’s loads with caution}
These were just for my Steyr hunting rifle and I never went further with it as I was just so pleased with the performance.
Now that I own a Garmin I will have to run that load and see what it clocks, your post has aroused my curiosity. I suspect that it is looking at 2860+ and perhaps edging 2900 with the 168’s.