Page 2 of 2
Posted: Mon Feb 06, 2012 12:56 pm
by WesternGrizzly
I shoot a factory non selected barrel. Yesterday I shot a 1200-98 at a NRA prone match. There are other times that I will shot a 10X clean on the 100 yard target taking up 1/2 the x ring.
I don't think barrel choice is super important, but when you can start averaging a 598 or so, I think its worth looking at. But until then, the money is better spent paying off people to cover your shift while you train. :)
I have been averaging a 585 or so for a very long time, and I KNOW its me. I have been having the same issue for the bast 1-2 years in prone, and I am finally finding the root cause, and working on it consistantly.
Matt
Posted: Tue Feb 07, 2012 1:42 am
by Levergun59
A little info on barrels. Stainless barrels are softer than chrome moly only because they are engineered that way. This is done to enhanse the machineability of the metal. Stainless barrell steel will resist flame cutting and throat erosion better than chrome moly, which is why the highpower and benchrest gents like it so much. It is not so much of an issue in a 22LR barrel.
Stress: single point cut rifling induces the least stress in a barrel while hammer forging is stressed to the max. Hammer forged barrels shoot very well for a certain amount of shots, then all of a sudden, poof, the accuracy gives out. For a regular hunting rifle this might be in the 750 to 1500 rounds, which really is a lifetime of shooting for a hunting rifle. Depending on the cartridge, a highpower shooter could get 7000 rounds from a cut barrel in 308 chrome moly and maybe 9000 rounds in a stainless barrel before throat erosion kills the barrel.
The Benchrest shooters always talk about hummer barrels that can shoot groups in the single thousanths. There is no way to figure out the criterion of such a barrel. They just happen to stumble into them. Magic barrels are the luck of the draw
Chris
Posted: Tue Feb 07, 2012 11:54 am
by justadude
jkuna brings up a very important point: never assume, just because the equipment is of some special pedigree, that the rifle is functioning as expected. I had a similar experience many years ago, scores were just so so but because of the pedigree of the rifle I was shooting it was just automatically assumed that there could not possibly be a problem with the rifle.... guess what, it was a problem with the rifle.
Even for an intermediate level shooter, it pays to occasionally throw the rifle on a sandbag, put a scope on top of it and shoot a few groups... just to make sure.
A little bit of the math behind this: The 10 ring on the 50m target is 10.4mm in diameter. The bullet is 5.6mm in diameter. To score a 10 the edge of the bullet must pass just tangent to the 10 ring. Add all this up and you can have a group 21.6mm in diameter (outside edge to outside edge) and still have all 10s. This of course allows the shooter ZERO margin for error, every shot must be delivered exactly correctly. As the ability of the rifle to produce smaller groups improves, the margin of error allowed for the shooter increases.
Different people will apply different standards as to what is acceptable, for 50 shot groups but from the chatter it seems the best rifle/ammo combinations can get down around 10-11mm outside to outside. If I had a rifle that was past 15mm I would start looking for a barrel change or better ammo or something.
Now, this does not mean that an iffy barrel is going to be holding a junior shooting 300 from 400 in standing back. The error induced by the shooter and the error induced by the rifle/ammo can be combined statistically and in a case like the one I just cited the error of the shooter is overwhelmingly dominant. Only when the shooter is producing scores in the mid-90s and up (per 10 shot string) would an iffy barrel start to, statistically, have an effect on the scores.
'Dude
Posted: Tue Feb 07, 2012 2:47 pm
by jkuna
Fact is that very high percentage of worlwide produced rifles isn't capable to shoot high scores. But, it is always easiest to blame the shooter. Only way to find out how good or bad you really are is to try to shoot with the rifle tested and proven to be good enough for tight groups.
We have planty of topics regarding group sizes on this forum and here is one worth reading
For whatever reason, international shooters/ammo makers do outside-outside group measurements. In general we also use 10-shot groups. I use many 10-shot groups to decide if a lot is worthy of trying it out of the shoulder. Eley uses composite 40-shot groups at their customer test range.
If all you are trying to do is get a lot that just cleans the international target, your group size is ~21.6mm...10.4mm ten ring + 2x 5.6mm bullet size (outside-outside). If I had a gun that had the best lot in that size range, the barrel is getting replaced. Heck, anything over 14mm is probably getting replaced.
Eric U
Pay attention on the last sentence. He is a great shooter and for shure he will shoot better with my rifle then I do, but to constantly shoot high scores he just need the best rifle-ammo combination.
Most of shooters use average rifle trying to shoot high scores, like I did,and seek for "non existing" errors. Years passing and there is no improvement, and only when they change the rifle, realise how many years of hard work they are lost in vain.
I am aware that not every one can shoot 600/600, but I think that whatever the level of competition is, we all hate to lose points.
So, I recomand to all, don't waste your time on worn out or poor barrels and wait to score 595 and only then seek for better rifle or barrel, it ain't gonna happen.
Not every rifle can do it even in a top shooters hands.
Do it if you can score 580 average and see how good really you are.
Posted: Tue Feb 07, 2012 3:59 pm
by KennyB
Just to chip in...
I've been using SCATT to help some of my clubmates - both are unable to hold the bull. There is no point either of them buying a new barrel as THEY are the weakest link... Now they both know it.
Once they can consistently shoot 600's on SCATT with group sizes in single figures, it's probably time to wonder why they can't do that with live ammunition...
My first rifle would occasionally put a shot in the 7 ring. It had shot a LOT of rounds.
I shot better than that barrel.
After re-barreling and a lot of work on my part, we're about equal...
K.