My Merkel combination gun tends to string sequential shots vertically. presumably barrel heating effect.

My question is whether there is anything I can do with reloading to minimize this? would lower velocities make less barrel heating?

Are there other old timers tricks I should try?

Obviously cooling down between shots is fine for target practice. but shooting at squirrels and rabbits with a 25/35 may not lend itself to waiting 3-5 minutes between shots.

the shots string up about an inch per shot at one hundred yards, when shot at 30 second intervals. This would be a bit much for trying to hit a three inch target.

regards

Is this with the scope or open sights? Did you just put the scope on?

The scope was mounted by JJ Perodeaux at Champlin. It is a pretty old scope though.

When the rifle cools down the POI seems to return.

My theory, or guess, is that teh bottom rifle barrel heats up, and bends upward since the cold shotgun barrel above is still at ambient temperature, causing teh rifle barrel to bow upwards.

Could something be happening in the scope?

My Sauer drilling puts the first shot 3" low at 100 yards so I aim that shot from the center of the dot and the rest from the top of the dot. I can shoot good groups with this system.

The scope for this use is a 4X Hensolt with claw mounts. I am always taking the scope on and off. The scope may be settling in on the first shot.

I use this gun a lot. It's the most effective gun I have ever seen if you want to get something.

I suggest that you just hold off on subsequent shots. If your gun is consistant it should work fine.

This never occurred to me. Both of my combo guns (Valmet in 12/.30-06 and Franz Sodia in 16/8mm JR Sauer) will put three shots in 3.5 inches. Good as I can expect with elderly eyes and open iron sights.

I dunno that I have ever had a shot over 100 yards when hunting with a combo gun and I am sure that I have never needed more than two shots on game with one.

Truth is that I only carry a combo gun when I am shotgun hunting with a chance of a shot on deer or deer hunting when the grouse are coming through. If I expected a shot past 150 yards, I would be carrying something else.

I have a Heym M55/77 in 20 Ga./30-06. It does not do this, but I don't fire a lot of rounds in rapid succession, so I wouldn't know if it would when it gets real hot.

Jarneister, double rifles, combination, and drillings are not designed to fire strings of shots. There is nothing wrong with your rifle, it is you that has the problem. It even possible to ruin your gun with long strings of shots from the rifle barrel. excessive barrel heat is the number one enemy od combo guns. The rifle was designed for ROE deer hunting, and as such may only be fired once a day, or several days. The shotgun barrel may be fired much more often than the rifle, because it doesn't create as much heat. Additionally, you need to be carefull with hand loads with this rifle barrel, as it was designed for factory ammo only, which are low pressure! Heat, and high pressure are NO NOs in this rifle. Merkel is a quality arm, and deserves proper care! I have a S/S 9.3X74R Mod 140E double rifle that shoots like a charm, and is fast becoming my favorite double!