vert

[bruce moulds]

looking at plot sheets of mine and others, as well as scoring and watching as others shoot, i have realized that i have never seen a rifle/ shooter/ ammo combo that can maintain vert equal to or smaller than the x ring for say 3 ranges of a prize shoot, or day in/day out.
the best consistent repeatable vert seems to be a bit bigger than the x ring in the real world.
this is of course after the barrel has settled down, which is another story in itself.
what is the experience of others?
keep safe,
bruce.

[AlanF]

My experience with 7mms would be similar to that. But I struggled for years trying to find a 6.5-284 barrel that would even hold the 6 ring all day. I now think it was the 6.5-284 chambering that was the problem - not sure exactly why - is it slightly over-bore?

Alan

[Matt P]

Bruce
We need to remember how small that X ring really is !!! Except for a few ranges is as small or smaller than 10 on the Champ target.

Matt P

[Norm]

I seem to remember reading something on the math and statistics of group sizes. Went like this..

If you have a rifle/shooter combo that can group 100% of its shots into 1/2 moa at a certain distance, 92% of the time. Or 1 standard deviation.

The they in all probability will group 100% of their shots into 2 SD's 97% of the time. That’s 1 moa!

Then there is the 3rd level that means that 100% of the shots will land within 3 SD's, 99% of the time. That’s 1.5 moa.

As you can see, the larger the group size the less often it occurs. This takes into account the occasional fliers and bad wind calls.
The thing is we only look backwards at the groups that the rifle/shooter combo has shot in the past. From that we try and determine how it will perform in the future.

With vertical dispersion I think it is a bit easier due to the lesser effect of wind. Good record keeping may help determine if one load is slightly better than another.

[DaveMc]

Another big thing is range conditions.

I am very lucky to have home range where almost every afternoon the stars align, lighting is perfect and it calms off with no mirage. In these conditions most rifles perform (not only mine but numerous others) much better than in normal day time competition.

If you get perfect calm, with perfect sighting (overcast conditions) for 3-4 ranges in a day -check those plots!

[bruce moulds]

alan,
i looked at an old fly target and thought my 6.5 gave better vert than the 7mm. but that is only one target!
dave,
how lucky you are with those conditions. if you only have them for testing, at least you can have faith in yourself and your tooling when things are less than friendly.
norm, you are dead right about record keeping. a lot can be learned that way. your explaination of s.d. makes a lot of sense in this context.
matt,
yes the thing is smallish, but we always live with a hopeful goal.
the 700 m target might be an exception to my statement sometimes.

i am often amazed by some of the statements on 6br and elsewhere, claiming certain rifles have certain levels of accuracy. either they live in very kind areas, have only fired one 3 shot group, or come under the heading of ganderballs. the same with some of the gunwriters in magazines,, and claims made by varmint shooters concerning consistently headshot rabbits at longer ranges.
bruce.

[DenisA]

looking at plot sheets of mine and others, as well as scoring and watching as others shoot, i have realized that i have never seen a rifle/ shooter/ ammo combo that can maintain vert equal to or smaller than the x ring for say 3 ranges of a prize shoot, or day in/day out.
the best consistent repeatable vert seems to be a bit bigger than the x ring in the real world.
this is of course after the barrel has settled down, which is another story in itself.
what is the experience of others?
keep safe,
bruce.

One thing I have definately noticed is how fewer f-class shooters actually consider and account for head and tail wind correctly, from shot to shot, especially the very fine adjustments.
I certainly don't do it well enough and its a current point of focus for me. I have seen recently how extreme the bullet drop can be with a heavy fish tailing headwind using a big .30. It was very eye openiing.

[bruce moulds]

denis,
shooting my 40/72 or 45/100, with black powder, there is somewhere between 1 and 2 minutes of elevation on the target when the wind goes from 3.00 oçlock to 12.00 oçlock.
the group obviously goes lower.
the first time i saw this i thought i had fired a bad shot, but time has proven it.
obviously white powder guns do the same, but less.
bruce.

[DenisA]

denis,
shooting my 40/72 or 45/100, with black powder, there is somewhere between 1 and 2 minutes of elevation on the target when the wind goes from 3.00 oçlock to 12.00 oçlock.
the group obviously goes lower.
the first time i saw this i thought i had fired a bad shot, but time has proven it.
obviously white powder guns do the same, but less.
bruce.

My real failing has been the very, very light breeze on my face or legs when the flags are indicating a crosswind. I need to train myself to acknowledge that breeze sooner and adjust vert accordingly. Quite often I've realised it was there too late. Anything more than a breeze is obvious and usually picked up.

I think that light breeze over range can cause a load not to hold its .5 moa water line in elevation in many cases....... not saying its the sole cause, nor am I saying that its the cause of your observations.

Just something I've noticed with myself and others.

I'm certain the majority of shooters on this forum are well and truely beyond that level including yourself Bruce. No offence meant if you took it that way.

[bruce moulds]

denis,
no offence, quite the opposite.
i started this thread to get discussion in the hope of learning something.
thanks for chiming in.
bruce.

[Brad Y]

I would put Bill Hallam and his millenium 308 up there for nomination. On days when we get our 308's into the 5 ring with vertical, his groups are flat. The man sure can read conditions and that gun has been terrorising opponents for the best part of two years. Its a shame WA guys dont get over there more often as we have some very good shooters.

Yet to do much shooting with my FO gun yet, still repeating ladders to show me what it prefers. 900m this sunday hope conditions are good. At 700m the vertical spread of 3 shots on the best load was 37mm and that wasnt good conditions.

[Lynn Otto]

Brad if you spend too long doing devepment/testing your barrel will be worn out before you get to do any serious shooting.

[Brad Y]

Haha lynn Ive only put 60 rounds through the gun! Just havent had a chance to use it! And will only put 24 though it this weekend before leaving it for a couple of weeks again.