I was reaching for answers in the Barrel Whip thread but had no takers, so I will try it again on my terms. Here in Texas ie. San Antonio area, we have had over 45+ days of triple digit temps. Why is he shooting in such conditions you ask? Because I do not want to wait until November when the temperature cools down to 95-85 degrees range. I have been playing with three problem children rifles. One in particular has been giving me fits. I am reasonalbly certain this rifle has a severe fouling issue despite all that I have done to it. But none the less this rifle and one other, both of which are aluminum pillar bedded, have had their points of impact shift dramaticly in the past three weeks. The severe problem child now shoots a 5 to 7 inch group @ 200yds. in a new location. I adjust the scope to the new location and it moves somewhere else. All barrels have been floated screws have been torqued and guns all have different brands of known-good quality scopes. I shoot out of metal building so direct sunlight is not an issue. One of the guns is not bedded at all but it's point of impact has also moved appox. 3". Yes there is a ton of mirage. Someday I would like to learn how to properly judge mirage. (Benchrest shooters do it in Texas)I have also allowed for the idiot shooter/rifle owner's bad shooting, but not 6 days in three weeks with over 50 rounds per session on three different rifles.
And now for my Question ---- Do any of you think that aluminum pillar bedding shifts the impact point in temperature variations? Aluminum moves like hell when heated. You would think if the barrel is floated, it wouldn't make any diff. But as I have read here on this forum "it is harmonics". G-Smiths and accuracy shooters input would be greatly appreciated.

Aluminum expands at .000018"/deg.C. A 10 or 15 deg.C change is not going to noticably effect your group. You have alot more chance of a scope being effected by the temp. and thats probably not happening eather. I would look at your crown's and bedding job. When a customer brings me a rifle that won't shoot like they want. Here's where I start.

1. Clean bore
2. Scope mounts and rings. Then the scope itself.
3. Bedding
4. Crown
5. trigger
6. Rebarrel - have only had to go this far once or twice.

Good luck........Tom

I can tell you this, there are a lot of close tolerance aluminum guns being used in some of the worlds hottest climates and heat doesn't appear to be posing much of a problem to them. The last I checked, the Marine Corps sniper rifles that are in use in these very same climates use aluminum pillars and have to maintain their zero's under extreme conditions and in extreme environments.

I doubt it is the bedding but in very hot weather the ammo may be causing higher pressures and that may change your point of impact. Also the "plastic" stocks can warp to some degree at higher temps.
I have had the exact same thing happen to me in very hot weather. Cold down to 30's does not seem to be that much of a problem.
Doubt it is the pillars unless they are loose.
Don't ever forget the scope maybe a problem but I do not know of elevated temps causing problems with scopes. John

I don't believe aluminum pillars will cause that, but mirage CERTAINLY can.

If you can, you might want to try a different experiment before condemning either the shooter or the rifle. Set the rifle up as if you were going to shoot it, at about 5 a.m.

Use a good, firm, steady rest fore and aft, and aim it at some very small point on the target that you might wish to hit.

Go away until about 9:00 a.m., then come back and without touching the rifle, look through the scope. Do the same thing again at about 11:00 a.m., 1:00 p.m., and so on every two hours until about 5:00 p.m. Do NOT touch the rifle or move it in any way, throughout that period.

What you may very well see is that during the day the rifle does not appear to be pointed at the same place on the target as it was at 5:00 a.m. If that is what you find, you can quit worrying about the shooter or the gun, and blame God.

(Just don't do so vehemently or without respect. In your part of the country He may still have toys like lightning and twisters to play with. You don't want to piss Him off...)

Alberta, I like your experiment idea and will give it a whirl. I think you are probably right, along with the temps messing with the chamber pressures some. I failed to mention that two of the guns have been accurized and barrel recrowning was part of it. As you may have concluded the idiot shooter is I. I am afraid I will be on Tapper2's No.6 (re-barrel) with my most severe problem child. The damn thing has been accurized by a much heralded accurizing shop, and I can't get it to shoot tight groups more than 2ea. 3-round salvos at a time. the groups have been as bad as 3&1/2" at 100 yards. This is with reloads using mostly Hornady and Sierra bullets. The "accurizer" used Hornady factory ammo. But I think the gun should still do just as good if not better with reloads. Another thing about it is I never know when and if it is going to shoot these tight groups.
Well another thing I did not mention was that these three rifles are Winchester M-70s circa 2005 and one 1985. You Remington people may now begin with your comments and sny remarks.

I have built 1000 yard rifles on both actions. There may be an accuracy difference, I haven't found it. Rem. actions are easier to tune, but to me, that's about it.

Have you scoped the bore of any of these?

Mirage can move your point of impact but I have never found it that great at 100 or 200 yards. I probably haven't shot in the temps you are talking about, eather.

I use Hornady ammo as my base load also. I would try Hornady ammo again and see if the accuracy comes back. If it does, back to load development. I have a 7mm Rem. Mag. that it took me a long time to find a load that would equal Hornady Custom ammo. Never could get better.

I fix a friends .416 RM by cutting two inches off the barrel. It went from 2" groups to sub-MOA. You can see him shoot a Buff with it on "You Tube".....Tom

One of your statements about scope adjustment got me thinking that maybe these scopes have a problem on all three of these guns.

I would take a scope off of one of your guns that does shoot and see if that improves them any.

Tapper2, I feel the same way about the actions as you, but it is the factory barrels where even I must admit that Remington is ahead of the curve. There is an older gentleman here where I live who is a custom stock maker (retired). He has built some very high end stuff, anyway he knows alot of the custom barrel makers as well as gunsmiths and award winning shooters. He told me that two barrel makers said that there is absolutely no reason why a Remington 700 should shoot as good as they do - it has to be their barrels! Yes you will get one from time to time that's a dud, but not often. It is my notion that Winchester barrels, post 1980,are hit and miss and some are just plain rough and take a long time to break in, if they will at all. As far as barrel scoping, ________ Accurizing Co. has looked down the barrel several times but only after the barrel has been cleaned with Wipe Out and everything is gone. I think I will have them look to see if they can see where, if at all, it is fouling after a shooting session.
Mgoodrich nothing is impossible but one of the scopes is a Zeiss Conquest with tactical turrets, one a Leupold Vari-X III, the other a Weaver Grand Slam. In my mind's eye it would be a fluke but, again not impossible. Thanks for your suggestions and help. I like these ideas better than the usual "I'd take the SOB to gun show and sell it".

Try keeping the ammo in a small cooler while at the range.

It is regularly 110°+ here and that little tip has helped my grouping.

I had a rifle bed by a "quality" smith and was great at first, then the pillars came loose and I had a hard time hitting a paper plate at 200 yds.

quote:

Originally posted by Tapper2:


Mirage can move your point of impact but I have never found it that great at 100 or 200 yards. I probably haven't shot in the temps you are talking about, eather.

Tom

If he does the experiment, it will be interesting to hear what he experiences. I have read reports by reliable reporters that go both ways. Some have said they found little change. Others found as much as 10". I don't know why the variances....maybe humidity, the amount of concurrent wind, angle of the light relative to the target, who knows?

I'm looking forward to hearing what he finds in his instance.

Have some experience in shooting at long range(6-1000yds as in prone/sling shooting)in hot weather as you describe and the mirage definitely plays a role in such shooting. There have been books written on the subject and I have just a small amount of knowledge compared to others, but will say a few things I have learned about shooting in such conditions are that never shoot through a "boil," beware if and when the mirage "goes away" all of a sudden, and remember that the target may well not be where you think it is due to illusion caused by the mirage. Boil as in water boiling in a pot, thermals if you will, may well cause the flight of the bullet to rise or go high. Mirage for me anyway is a far better indicator of the winds than most flags and was always taught that if the mirage disappears(flat line) the wind has most likely gone above 10-12mph range and would require either not shooting or apply apropriate windage. I prefer to "hold up" if possible to shoot in favorable conditions, not always possible. Have observed in heavy mirage conditions the bullseye appearing to be almost oval or elongated horizontal and obviously the target itself did not move, but in your vision/percection it did. I find that even high quality rifle scopes are a poor instrument for reading the mirage/wind conditions compared to a good spotting scope(Kowa.) Suggest using spotting scope focused short of the actual target and observe all the strange gyrations of the mirage. At times looks exactly like a river flowing one way or the other then it will go flat and then will go vertical/boil. Adjust according to what you see, but should qualify that my shooting is not for groups or as precise as you are doing, but my primary goal is to keep it in the 10 and X ring. As mentioned at ranges of 1-200yds would not think as critical, but the mirage/wind is definitely there. Fellow by the name of Jim Owens has written serveral books on shooting and has one on reading wind and mirage. Good info and often go back and re-read. Am sure others out there can offer more info than above but just some basic tips that have helped me over the years.

Well, I'm up the road a bit from you, north a couple hundred miles. I have been working on some loads in this 100+ weather also. On Mirage, I agree to not shoot in a boil, it can be displacing the image, I have trouble shooting groups in these conditions. I prefer to shoot early in the morning this time of year if I can.

I do not think the aluminum bedding is your problem, it should make things better, not worse. I would check to make sure the barrels are actually floated. Make sure the stock is not warping and touching as it heats and cools, and make sure nothing has gotten lodged in the barrel channel, that can sometimes happen as well. Some rifles are also hold sensitive, try and be sure you are holding the rifle the same every time.

I definitely appreciate your input on the mirage and checks MFD and JTPinTX. I am the worlds worst about not holding the rifle the same way twice and I even know better. I just get focused on something and forget about the other. I noticed the boiling mirage and total disappearance of it and figured it had alot to do with it. But again it was at 200 yards but I also live in farm country where the winds blow and shift quickly. I too try to shoot early and late, but not always able.

Here is another "for what it is worth" post:
I met a gentleman in Laredo, Tx. who had a 338 Lapua in one of those LONG range shooting jobs (had a 20x plus NightForce scopes on it). He said he shot 800 to 1000 Yards regularly. For those of you who know nothing about Laredo, Tx., it is Texas' equivilent of Phoenix AZ. Temperatures get to 110F regularly. I asked him how he liked the high powered NightForce scope. He said it was a very good scope but that high of power was pretty useless on hot days because of mirage. He stated that he found 8x to be about as high as he could go on those days. After he said that, I remembered reading that the military sniper rifles of the 60's and 70's were typically equipted with 8x Ubertal scopes.
Well Saturday, on another one of our 100 degree plus days, I had another shooting session but this time I left all of my scopes turned down to 8x. The shooting session was "a lot more" productive. Groups were tighter and the point of impact was a lot more consistant with where it was suppose to be. I am still having trouble with one rifle in particular with fouling but the impact point was correct despite the varying group size. And the third problem rifle, well, read my post in Medium Bores under "Are factory Tikka T-3 rings adequate?"

Rae,

With that barrel that's fouling bad for you, I think I would scrub the bore good with JB Bore Paste about 100 strokes to polish it so it stops fouling.