I'm looking for suggestions here.

I have a Ruger Mark II in 300 WM that I've been trying to develop loads for. The issue that I'm running into is that I can't really geta good idea what a particular recipie is doing because it gets really hot. It basically refuses to cool down.

The range is far from my place and as far as I can tell it takes longer than 2 hours for it to come back down to normal temperature.

Am I going to have to develop loads in the middle of winter?

Tom

Simple.Drape awet, but not dripping, dish towel or some other sort of rag over the barrel. It'll cool it down in short order.Just make sure you re-oil the exterior of the barrel when you're done shooting for the day.

BTW, I never shoot my .300 WM (or any other rifle for that matter except a .22) more than 3 shots at a time before cooling it back down. During the winter, the wet rag is usually not necessary. Then I just set the gun up vertically and open the bolt so that air can flow up through the bore like a chimney.

DM,

If you were using the wet rag to cool the barrel would it affect the next group? Meaning a specific combo might group well with a hot barrel that has been cool but won't group from a cold barrel?

Could I just bring a bucket and dunk the barrel?

Tom

I'm not sure exactly what you mean, but let me just say that I'm assuming that your rifles are for hunting. If you're like me, then the only shot that reallymatters is the first one from a cold barrel. So therefore, I don't care at all how my rifles shoot with a hot barrel cause I'm never going to be shooting them that way in the field.I want my barrel as close to ambient temperature as possible before shooting the first shot of a three shot group.

As far as dunking the barrel in a bucket of water, well, I'm not sure that would be a good idea unless you plan on pushing a patch through the barrel to make sure there was no water left in there before you shoot it again. Besides, you can't submerse the entire length of the barrel anyway without getting the stock wet unless you're going to take the action out of the stock. It just doesn't sound like a good idea to me. The wet rag idea is so simple and easy I can't fathomwhyanyone wouldwantto make itmore difficult. A benchrest shooter showed me this a few years ago and it has worked great for me ever since then. Next time you're out shooting, give it a try.

I watched a guy use CO2 to cool his barrel down it was a little bike tire pump that used 12 gram CO2 cartridges with the the threaded nozzle cut off he would put the rubber hose in the chamber and squeeze off the CO2 for a few seconds and the barrel was very cool to the touch. you might give that a try before dunking the gun in water. good luck

I think that bullet friction has more to do with barrel heating than powder type. Try molly coated bullets and see if your problem doesn't improve. How hot does it get in Michigan anyway, here in Alabama even in August it doesn't take more than 20 minuates for a barrel to cool.

When I'm on the range in the summer, I rotate rifles and pistols to keep em cool.For new loads, I'll load up 15 rounds and shoot them in 3 shot strings, cooling between strings.
I always bring along a 22 rifle to shoot while others are cooling down. On really hot days I'll put hot rifles in my truck with the a/c on for a few minutes, then lay them on the bench to equalize fora bit before shooting. I also usehomemade mirage shields made of a window blind slats to keep the "fuzzies" down when sighting through the scope.

I have the same gun that you do in .300 WinMag. Have not found it to get any hotter that other guns I have in .30-06, .308 or .300 WinMag. I seldom fire more than one roundper minute. After each three shotgroup let it cool forfive orten minutes with the bolt removed. It will cool down much faster with the bolt removed than with the bolt open.

Saw a guy on the rangeat Ft. Sillruin his .300 Weatherby MK V Magnum barrel intwo range sessions.He was trying to sight it in with a newhigh dollar scope. He hadkilled an elk at over 500 yards the year before with that gun using an in expensive scope-should have left success alone.

Several shooters told himthat his rifle was too hot. On the third visit to the range another shooter inspected the bore using his spiffy expensive bore scope. There was no visible rifling for the first four or five inches of the bore.I think thathe ruined the barrel on his first range sessionwhenhe fired40 rounds of Weatherby ammo through it in about one hour.

I useIMR 4831 for 150 and 180 grain bullets-works well for me.

Good luck with your load development.

I found 4831 to work well too. I working with RL-22 right now and not getting nearly the same results. Have you tried anything else?

Tom

That has not been the case at all with my own guns.I have used coated bullets,and they produced just as much barrel heat.
That being said, I never have to wait more than 20 minutes for a barrel to cool.I do my load development in temperatures around 70 degrees.