I have had some problems with my 270 and I think I might know what I have been doing wrong. I noticed that after 3-4 shots I am seeing heat distortion out of the barrel threw the scope. This is something I am use to and familiar with when it comes to black powder but not modern firearms. After looking at previous 270 targets I noticed that my first two shots are almost always right next to each other. Then I noticed that if I took my targets from my last two trips to the range and stack them I have some really nice groups (when comparing “like loads”.) Could my problem with this barrel be that I am just shooting too quickly at the range? Could my muzzle tamer be adding to the heat distortion?

This is a hunting rig and not a “bench gun.” I can handle this problem if I just know it is a variable with this barrel… or I should say more of a variable with this barrel. LOL

How much time are you taking between each shot? One way to check your theory would be to shoot two and then wait an inordinate amount of time before your next and between the following shots. Depending on how heavy the contour of the barrel will affect how quickly it heats up as well as disperses heat. Are your latter shots striking lower than the first? When I was in the Army we observed several tests with M60 and 50 cal MG's which were locked down and then fired a steady stream of tracers and the downward movement of POI was obvious, and significant, as the barrels warmed up. Heat will make a difference, no doubt, just how much is variable.

Probably 30 seconds or so… but I think you are right on S4S4U. The next time I go to the range I planed having plenty of cool off time in-between shots. I am use to heat distortion affection groups in firearms, but I am not use to seeing “steam” in the scope. It almost looked like I am looking down my 20 flintlock and it just kind of bothers me that I haven’t noticed it before. I just have a funny suspicion that if I take my time next time the results are going to be a lot better at 100 yards. I didn’t have this problem with my other 270 barrel and I was just wondering if my suspicions could be right.

It could also be the fouling of the barrel. My 22 lr match barrel has a very noticable difference of POI between clean and fouled barrel. At 25 yards it will be a 3" difference. Might be something to check, although heat could do the same thing.

I have seen both heat and clean barrels cause POI differences.In several calibers of the 700 mountain rifles with the pencil barrels,after about 3 consecutive shots the POI changes and groups will grow.I have a heavy barreled 308 that hates a clean barrel.I have shot some amazing groups with this one but only after a few fouling shots after cleaning.It got so when I cleaned it I would just grab about 10 rounds and shoot them in a dirt pile from 25yards then I would set up and shoot some groups or hunt.I know my experiences all pertain to long guns but I would think it would still apply.

my 300win mag also hates a clean barrel it takes a couple of fouling shots for it to settle down and the things are good.
tcman i have a ruger 270 ultralite rifle that does suffer from heat. i shoot it yhen lay it down action open shoot a different gun then go back to it . by doing this iam able to get half inch groups with this gun at 100 yards.

TC Man,

I know what you mean - I have a 257 Weatherby Mag that shoots exactly where I want it too, when cold! When the barrel starts to heat up (which is very quickly after rounds 2 or 3), it starts to spray...

But it's a huntin' rig - and only one shot is needed, right?

As others have suggested, let that gun rest for several minutes between rounds, and see what happens...

When working up loads or sighting in for the first time each season, I will let any gun I'm shooting sit for a while before shooting an additional round. Last summer, on an 85 degree day in direct sunlight, I conducted a simple experiment just to see if a HOT barrel made a difference in POI in my blued Model 70 Classic Laminate in .300 WSM. I started with a clean barrel and got sighted in with two, 3 shot groups which took me about 15 minutes. The groups were typical of what that gun shoots with that load; 67.5gr IMR4831 and 180gr Accubonds (~MOA). I then immediately commensed fire on a new target, firing 15 rounds (of the same load), loaded one at a time, all in under 3 minutes time. The barrel was obviously too hot touch afterward but all of my shots were exactly where I wanted them and with the exception of two flyers (my fault), stayed under an inch and a quarter.

I have had barrels that I could shoot all day and not really affect groups. As a general rule, larger boars are not as sensitive to heat as smaller boars. My old 22 Hornet would shoot lights out, but after 4 shots of quick firing it would start to walk a little. I think my 270 is a shooter, I just think it is sensitive to heat. Time will tell. If heat is not the issue it will be time to buy a couple more pounds of powder. LOL

The only problem with heat sesitive barrels is the time waiting for them to cool. Bring a 22 along to make the time go a little quicker. Good luck, James

Good suggestion james.

I don’t go to the range without 4-5 play toys… LOL