You think shoot sub-moa all day long huh

[stagpanther]

By sheer coincidence, I just got back from shooting my savage axis build that I re-barreled from 6BR to 30BR. I think the 30BR is quite possibly the most accurate shorter range cartridge ever designed, possibly even more so than the 6PPC. Having enough experience with the 30 BR, I knew in advance there was no way I could miss shooting 10 shots under MOA unless I really goofed up--which in fact I came pretty close to doing. I shot these at 173 yards with a moderate crosswind of 10 mph +/- I used berger 115 target bullets propelled by H4198. As with previous attempts I shot 10 shots only with no sighters/foulers and in this case, the very first cold and clean bore shot is the one that landed high and right. My 25 creedmoor's first shots tended to land low and walk up--whereas the 30 BR landed high and tended to walk low.

Here is the group scored including the clean/cold bore shot, which still came in a bit under MOA:

Here is the same group scored without the first cold/clean bore:

As nice as that group might look, I actually called 3 fliers as the shots broke because I could see that I pulled them. It may sound like sensationalistic BS; but ask any comp shooter who has experience with the 30 BR and I'm sure they would agree that even this level of accuracy/consistency would not be competitive.

That's how good the 30 BR is.

 

[tangolima]

300yd .22LR is hard to do. Compared to wind effects, cold bore shift probably is insignificant.

-TL

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[Dave P]

I was amazed to see so many just jerk the trigger, and immediatly release. May be due to the video, but looks like poor trigger control to me. I always squeeze the trigger, and hold it back. then release it. (2 stge mil trigger)

 

[Stressor]

M193: no (nobody does)
Match ammo: always

 

[georgehwbush]

(Thanks--but personally I think Franken's friend spread a special on-line virus to cause 10 shot groups to disperse widely.) agreed.

i think i will see what my savage axis 223 will do. it's windy so i may have to use that for an excuse if needed. ))

 

[stagpanther]

i think i will see what my savage axis 223 will do. it's windy so i may have to use that for an excuse if needed. ))

You obviously haven't read the book I wrote; The Complete Shooter's Guide to Excuses.

 

[tangolima]

Outstanding group at such distance and wind, Panther. I can see your rifle settled well within 3 shots, and the shift is pretty minor (0.5moa). Mine usually take more, 10 shots is quite common, and the shift is 1 to 1.5 moa.

I suppose you kept the same POA for all 10 shots. The 8-shot group I did, I adjusted the windage hold each shot based on the previous poi. The small piece of white paper is 1/8 sheet of letter size printer paper. It is my practice target. All 8 shots hit.

-TL

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[stagpanther]

Outstanding group at such distance and wind, Panther. I can see your rifle settled well within 3 shots, and the shift is pretty minor (0.5moa). Mine usually take more, 10 shots is quite common, and the shift is 1 to 1.5 moa.

I suppose you kept the same POA for all 10 shots. The 8-shot group I did, I adjust the hold each shot based on the previous poi.

Thanks--the 30 BR at close range is about as close as you can get to a "can't miss" cartridge in my shooting experience. I think my takeaway from these few groups is that "yes, there is at least one shot from a cold clean bore that is going to have a predictably different impact from the rest of the shots taken." That doesn't mean it will always deviate in the same way regardless of the rifle used. I would need to shoot more, but I think it's really only the first shot from a cold clean bore that is going to deviate from the rest in a significant way--unless the bore itself has flaws that benefit from repeated shots fouling building up. So the next few groups I shoot I'll foul first and see if that has any benefit. I did not "chase the impacts" and agree with Cleckner on this.

 

[stagpanther]

300yd .22LR is hard to do. Compared to wind effects, cold bore shift probably is insignificant.

I don't think 22 lr has cold bore shift like centerfire does. Clean bore shift--yes.

 

[tangolima]

I don't think 22 lr has cold bore shift like centerfire does. Clean bore shift--yes.

I think you are right. Should there be any, it would be very slight.

-TL

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[tangolima]

Thanks--the 30 BR at close range is about as close as you can get to a "can't miss" cartridge in my shooting experience. I think my takeaway from these few groups is that "yes, there is at least one shot from a cold clean bore that is going to have a predictably different impact from the rest of the shots taken." That doesn't mean it will always deviate in the same way regardless of the rifle used. I would need to shoot more, but I think it's really only the first shot from a cold clean bore that is going to deviate from the rest in a significant way--unless the bore itself has flaws that benefit from repeated shots fouling building up. So the next few groups I shoot I'll foul first and see if that has any benefit. I did not "chase the impacts" and agree with Cleckner on this.

Not disagreeing on chasing impact. I mostly do it to adjust windage due to changing wind, preferably after observing >2 shots in a row shifted in similar manner. Sometimes, .22lr over 200yd or air gun over 100yd for example, I also adjust elevation as per bullet's gyroscopic properties. Increased cross wind from right, poi is to hit left-high, right-low vise versa.

-TL

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[stagpanther]

Not disagreeing on chasing impact. I mostly do it to adjust windage due to changing wind, preferably after observing >2 shots in a row shifted in similar manner. Sometimes, .22lr over 200yd or air gun over 100yd for example, I also adjust elevation as per bullet's gyroscopic properties. Increased cross wind from right, poi is to hit left-high, right-low vise versa.

And I agree with that--but how do you know what your actual POI should be without assuming no external influence? This happens to me frequently in windy conditions--a few shots may land up and right of the point of aim by a half foot, and I adjust the scope or holdover to hit the POA. Then, low and behold, the next few shots hit low and left by the same degree from the point of aim.

 

[tangolima]

And I agree with that--but how do you know what your actual POI should be without assuming no external influence? This happens to me frequently in windy conditions--a few shots may land up and right of the point of aim by a half foot, and I adjust the scope or holdover to hit the POA. Then, low and behold, the next few shots hit low and left by the same degree from the point of aim.

There isn't a definite answer. We are basically trying to predict what would happen in the future, however near it would be. The only thing we can do is to getting better in picking up clues. That is the value of a good shooter. He is adaptive to the changing environment.

Many a time I found myself overcompensating the cross wind. Neglect to realize the wind has died down.

-TL



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[stagpanther]

I can't tell you how many times a fly has landed on my target that I then mistook for an impact. I shoot at a site where there is a large dump with decomposing compost--there are lots of flies there. On the plus side they are fun to shoot with a 22lr.

 

[FrankenMauser]

Stagpanther, that is a very nice group.
Don't sell yourself short - especially since you know when you screwed up and could call the shots.
Very nice.

I think you are right. Should there be any, it would be very slight.

In the past, I would have agreed.
But as a lover of rimfire rifles*, and a person that has been chasing improvement in the precision rimfire world for a year and a half, I must now disagree.
*(At this point, I may have more .22 LR and .22 Short rifles [plus one .22 WMR and one .22 WRF] than any other category or type of rifle or shotgun. And most of my .22s are inter-war production. They made some amazing rimfire barrels back then.)

Some .22 LRs have really terrible cold bore shifts. Usually, they are semi-autos, suffering from the same thing some centerfires have problems with: a bolt closed manually, vs normal (automatic) cycling. But I've run into a few rimfire bolt guns that throw the first shot, as well.
And while it may only be, say, 1/2" low, left, whatever, that 1/2", when the standard zero range is 50 yards and the expected precision is sub-moa, is pretty bad. It is more than doubling the group size.

 

[stagpanther]

In the past, I would have agreed.
But as a lover of rimfire rifles*, and a person that has been chasing improvement in the precision rimfire world for a year and a half, I must now disagree.
*(At this point, I may have more .22 LR and .22 Short rifles [plus one .22 WMR and one .22 WRF] than any other category or type of rifle or shotgun. And most of my .22s are inter-war production. They made some amazing rimfire barrels back then.)

I didn't mean to imply that a shift doesn't happen--it most certainly does. But I've gone out and shot hundreds of 22lr rounds in my pencil-barreled CZ jaguar and have yet to see the barrel actually get hot. I watch the chambers and bores obsessively with borescopes on all my rifles to get an idea of how they foul and with what powder/bullet combinations. In the case of the 22lr rifle barrels I have, what I've observed is that the residual lead and lubricant build-up in the chamber and the (very short) free-bore/throat is in my estimation probably responsible for most of the major shot shift in 22lr. Just my opinion, can't prove it and could be totally off-base on that. This has put me in the mood to get some 22lr action out and I think I'll try that next.

Thanks for the compliments--a well-tuned 30 BR should be getting at least .3 MOA at reasonable distances; it's not unusual in ideal conditions for good shooters with good gear to be getting down into the .0xx MOA (!)

 

[davidsog]

That's really what I'm trying to find out; how and in what way does the first cold clean bore shot differ from the rest of them. Why? Because IMO a cold clean bore is the only real definite starting baseline you can be absolutely sure of repeating in order to pattern how your barrel responds when starting a new shooting session. Each bore is going to respond differently, but there will likely be a "foul in" and warm-up "seasoning" of the bore as the continuous shooting session progresses.

The role of fouling is something that is difficult to pinpoint in a predictable way and is going to vary with each bore IMO. So many variables come into the picture; but I would say in my experience it is pretty evident that fouling in some ways does provide a "balancing" function and at some point there is an increase in repeatable accuracy and consistency. The evidence is pretty obvious--with each subsequent shot the bore is progressively being coated with carbon and metal residue.

I was also trying to pinpoint to what degree the shooter's variability affects the patterning of the shots. I know that in my case that is the source of the greatest variance in my shots. I think that is what Cleckner is alluding to in his comments about the usefulness in dry-firing prior to shooting. I've always done that myself, not so much for flinching conditioning, but as a way to see how the rifle moves as I progress through the hold and the moment of the trigger's break (it's also the reason I shoot 22lr a lot--it's one of the best ways I've found to magnify how the shooter's technique affects the shot IMO) . Beyond all the chemistry and mechanics relative to the hardware and ammo--it actually requires a lot of concentration and coordination to really get skilled at repeatability of shooter's technique for me; 10 shots held and sent in exactly the same way is quite hard to do if you are not equipped with top-of-line equipment and have the luxury of an ideal shooting position with all the time in the world to set each shot up IMO.

As always, other than the fact that I simply shoot a lot, I don't claim to have any expert training or experience to back these observations up and don't claim that they are immutable laws of shooting, just what I've found in my personal fun-time shooting which is really a recreational hobby for me in my sunset years.

You have got the right idea.

A good Sniper Logbook will have a place to plot your Cold Bore Shot. You measure from your point of aim and record the location of the Cold Bore with measured data.

Over the course of multiple trips to the range, you build a "group" of your Cold Bore shots.

You take a target and plot out the Cold Bore Group. You then record your sight adjustments to get your "Cold Bore Zero".

The next time you go to the range, you change your scope dope to the cold bore zero for the cold bore shot and the process starts over again.

It takes a bit of effort but the end result is a much more accurate first shot. Just remember to put your scope dope back to your warm bore zero.

 

[davidsog]

Good Shooting Stagpanther.

 

[stagpanther]

Thanks David; I've always been a big Carlos Hathcock fan who maintained that only one shot really counts for accuracy--and that's the first one off a cold clean bore. I can see why he felt that way since his life often depended on that--and the probability of ending his target's life did too.

I actually have a long-range sniper caliber (338 LM) rifle that is a relatively cheap mass-produced lightweight rig that can take a target down at a mile or more assuming your brain and teeth survive the concussive reports. I'm considering trying it out in the 10 shot challenge just for grins; problem is I try to shoot it at at least 300 yards cause I firmly believe that very high SD bullets do benefit with range distance to obtain optimal gyroscopic stability. Unfortunately quarrying activity is going to limit me to 170 yds +/- for the time being.

Over the course of multiple trips to the range, you build a "group" of your Cold Bore shots.

You take a target and plot out the Cold Bore Group. You then record your sight adjustments to get your "Cold Bore Zero".

The next time you go to the range, you change your scope dope to the cold bore zero for the cold bore shot and the process starts over again.

It takes a bit of effort but the end result is a much more accurate first shot. Just remember to put your scope dope back to your warm bore zero.

Very cool and makes a lot of sense. Thanks for that.

 

[davidsog]

I firmly believe that very high SD bullets do benefit with range distance to obtain optimal gyroscopic stability.

That makes sense. SD divided by Form Factor is your BC. Higher BC tends to shoot flatter to a point. Consistency is the key. The more you can eliminate variables and reduce the margins of error, the more accurate your shots will be.

For some things, we handloaded each round and zero'd for that batch just to eliminate as many tolerance variables as possible.

As a rule, we zero'd our rifles by lot number of Match ammo for general use. In theory that Match Ammo lot was loaded to the same tolerances.

Unfortunately quarrying activity is going to limit me to 170 yds +/- for the time being.

Your range is limiting but not crippling in my opinion. Nothing replaces actual experience so its best if you can confirm the assumptions at actual distance. You know this too, lol.

We zero'd at either 400 meters for a Point Blank Zero for General Ops.

We also Zero'd at 100 meters for extreme long range and then adjusted our scope dope.

I made headshots at 1000 meters with a .308 routinely on a rifle that was zero'd to 100 meters. Different ballistics from 338 LM of course but the principle applies. Knowing your Optic is very important to being able to do that, too.