new barrel - which .308 chamber ?

[Sam Walker]

I've got a Mk X Mauser FB rifle with a worn out Schultz & Larsen barrel, and am getting psyched up to fork out for a new (stainless) barrel.
I know there's a few versions of .308 chambers around, which ones would be OK for F Std ? I wouldn't mind something with minimal neck clearance and giving the case necks a bit of a light turning if it would be within the rules. I'm thinking to buy from MAB or Maddco, sending the barrelled action to them to fit the new barrel. No gunsmiths/shops around here !
Anybody have any advice/recommendations ?
thanks
Sam

[Tony Z]

edited 19/4/06

[bruce talty]

I've got a Mk X Mauser FB rifle with a worn out Schultz & Larsen barrel, and am getting psyched up to fork out for a new (stainless) barrel.
I know there's a few versions of .308 chambers around, which ones would be OK for F Std ? I wouldn't mind something with minimal neck clearance and giving the case necks a bit of a light turning if it would be within the rules. I'm thinking to buy from MAB or Maddco, sending the barrelled action to them to fit the new barrel. No gunsmiths/shops around here !
Anybody have any advice/recommendations ?
thanks
Sam

Hi Sam get a MADDCO 1X14 3 groove 30" that what Nev Madden reckomends for 155 Palma bullets he has a good palma reamer they could do the whole job for you Ring Tim Hughes at MADDCO 07 4634 5622 PS they don't work on Friday.

[Matt P]

Be careful with a 14" barrel at long range have seen some funny groups which look a lot like bullets not being stable.

Matt P

[bruce talty]

Be careful with a 14" barrel at long range have seen some funny groups which look a lot like bullets not being stable.

Matt P

hi Mat Have never had a problem with any before using the 155 grain bullet and have had 4 others in 7.62 Full bore barrels and have shot 168 in them, shot 73.13 at 800MIpswich missed a drop off and a wind angle change and Ipswich would be one of the hardest ranges to shoot in QLD, i have a 28" one and have shot it at 1000yds with very good elevation they shoot better groups than my 30"12"and34"13" twists at the long ranges. i have shot 1200 yds with the 1X13" 34" with 154 Lapua. was the weather very cold below 10*C you might have a bit of trouble Bruce

[Tony Z]

edited 19/4/06

[bruce talty]

The SF for a 155 SMK in a 14 twist is 1.81.
1.5 is where a bullet is maximally stabilised, 1.3 is where it is fully stabilised and 1.0 is the go if you dare area which in the case of the 155 SMK would be a twist rate of 1 in 18.9. The main problem i see with the 155 Sierra is that some batches i have measured have a great spread of dimentional changes in the ogive profile. Henry Childs in the US recently ran tests with this pill and reported BC variation within one batch of almost 20%. The lower end being .420 and the upper end being over .500. With meplat cutting, which we can't legally do, the spread was reduced but was still not great. At long range this in a left to right wind translates into a high shot left of group center with the higher BC bullet, and a low right of center of group shot with the lower BC bullet. If you're speed is down the lower end of the BC may be enough to get you real close to that transonic period, or indeed below the speed of sound. You may be thinking that a condition may be getting the better of you, but i have spotted behind some of the best FB and FS shooters around and i know it aint the conditions. I have had little to do with the Dyer but i recently watched Arthur Simpson, who some of you older FB guys would know well, shooting a FS rifle at 900 M and was very impressed with the little vertical shown in his groups using the Dyer.
Tony Z.

G'Day Tony i don't use SMKs only Dyer and Lapua and i also have that program in Excel as well and others and they all thell you about the same.Bruce

[Tony Z]

edited 19/4/06

[bruce talty]

Bruce,
I am using the Winload program that requires profile measurement aswell as measurement of meplat to core etc. The BulletStability program you are refering to i also have and the two give almost the same figure. But like most programs i only use them as a guide. I have shot the 155 SMK in an 18 twist and it has grouped flatter at 500 M with the same pills shot in a 14 twist but that was a different day in a different rifle so that one test is inconclusive. But stable is stable and there was still too much vertical to make me want to rush out and build a worldbeating FS rifle because no matter how good the rifle is, it won't change a bullets BC irregularities when one goes to the 900 M line. But then there is the Dyer. What is their length, the length of the nose and their secant ogive and how far from the meplat is the core? If some-one could pass this on to me please.
Tony Z.

G'Day Tony Dyer 1.131" Lapua1.287" Sierra 1.135 Nosler 1.142 Berger VLD 1.245 all these shoot very well in my 28" 1X14' 3 Groove out to 1000 yds air density makes a big differance on hot day up here 35*C+ they shoot 2' flatter at 1000 yds than say 25*C. On a very hot day Lapua 154 from 100 yds to 1000 yds 28', Dyer 30'. Bruce.

[RDavies]

It is making me think about getting a 15" twist barrel to experiment with. I see that MAB is making 15" twist barrels in cut rifling. I hope the 15" twist will stabilize the 155gn bullets in the warm weather up here.

[bruce talty]

It is making me think about getting a 15" twist barrel to experiment with. I see that MAB is making 15" twist barrels in cut rifling. I hope the 15" twist will stabilize the 155gn bullets in the warm weather up here.

it might be alright to 300 yds but after that you might be unstable. bruce