30/30 Not Shooting to POA?

[Sulaco]

I bought a Marlin Model 36AS 30/30 the other day. I took it out the day I bought it and shot it some. It shot to POA for 2 three round groups, letting the gun cool between groups. I fired the first three shots using the mounted, Tasco 4x32 scope. The second three shots I shot using the iron sights (it has the kwik site rings). Both groups were less than 3 inches at 100 yards. I was fairly impressed.

I took it to the range today and shot it and it was way off from where it was. I used the same ammo (out of the same box even) and haven't done anything but clean the gun since the last time I shot it. I have been very careful with it and have kept it in a hardside case. I let a friend shoot it and he experienced the same thing as I did. The gun now shoots about three inches low and 3-4 inches right from where I aim. I use a gun vise or some sand filled rests and get the same results. I shot it standing and had the same results. I EVEN had the same results using the iron sights in all of the same shooting positions. I let my friend shoot it again, this time using the iron sights and he had the same problem I did. The groups are spreading out more and the first shot of the day was a flier.

What is wrong with this thing? Is it something simple I am overlooking or what? I don't think just cleaning it could have this effect. I have been shooting (hunting and pistol competition) for years and this is just baffling to me. Please help.

 

[Delmar]

I would check every screw on the thing, from the handguard on back-they do have a way of backing out on you. Pay particular attention to the scope, rings and mounts, and make sure the wood is completely sealed in all areas. Also look at the conditions of the two range episodes-was the temp/humidity and all that pretty much the same?

 

[Sulaco]

Well, the temperature was about 20 degrees cooler today and the humidity was higher since it was raining. I checked all of the screws and the scope mounts (rings) prior to both sessions. Could the temperature/humidity difference throw it off that much? If so, it would be the first I have ever seen it affect the POA that much. Thanks for the reply.

 

[Capt Teach]

Check the muzzle. It's possible if you were too enthusiastic when cleaning, that you damaged the crown of the muzzle. Did you use a steel cleaning rod?
The screws and bands are always a possibility, but I've never heard of anyone tightening them everytime they went to the range. Use some locktite, make them snug and that should be it, unless you disassemble the rifle.

Capt Teach