hot barrel - accuracy

[camp_13]

I aquiredan older Remington 742 in 6mm, love the cartridge, but not sure about the gun, yet. It feeds flawlessly but after the first couple shots the accuracy goes in the tank, my gut feeling is the scope is wacked (its a cheaper bushnell) but the barrel was gettin a little hot, how many inches off can a hot barrel cause?

[missed_another]

a warm barrel can be real bad on your accuracy. most every gun that i own except for my .22 long rifles and my target rifles with heavy barrels the groups start opening up after 4 or 5 quick shots. you should allow a minute or two between shots for the barrel to cool down. the lighter the barrel the quicker it will heat up. this is only draw back of the light weight sporter barrels. but they are much easier to carry all day.

[trailer]

I had the same problem with my 742 chambered in a 308. It would shoot good until the barrel got hot and that wasn"™t very many shots. I wouldn"™t blame it on the scope just yet.

[jmfa1957]

I've got a 742 in .30-06. It also has a cheaper Bushnell scope. Over the years I have found that this rifle will deliver pretty ho-hum accuracy, 2" to 3" groups @100 yards, with just about any load including a variety of handloads, unless I let the barrel get COLD between shots. If the weather is cool, if I let the barrelcool thoroughly between shotsand if I am using Remington 180 grain CoreLokt factory loads, it will print 1" groups at 100 yards. This satisfied me that the cheap scope is not causing POI to wander, barrel heat is.

[Briman]

I've seen hundreds of of 742s and 7400s, and its a very rare one that does shoot good after 3 or 4 shots.
The problem is that there is too much stuff bearing on the barrel. When the barrel metal heats up, it expands. On the 742s and 7400s the only direction for the barrel to go is to warp one way or another. On a good note, most of them tend to shoot good enough for hunting accuracy, and if used for hunting, there seldom is a reason to shoot more than once or twice anyhow.

[camp_13]

Thanks alot, I am going to try it again tomorrow and let er cool down after each shot.

[camp_13]

Just an update, OK, I shot the 742again, Iwaited several minutes between shots, barrel hardly even warm. Still terrible - 6" to 8"groups at 100 yards, I am going to change scopes now and really give the barral a total cleaning. It's a fun rifle to shoot I hope I can get it squared away.

-Camp

[jmfa1957]

Wow - - 6" - 8" groups? Uff da! I think there is definitely something else going on here besides barrel heat. I did have a cheapie Bushnell 4x go south on me recently after 20 years of intermittent service (never used it on the 742 though.) Something is rattling around inside (bad sign) and the windage is no longer adjustable.

A thorough barrel cleaning to get rid of copper buildup, a check of the crown for nicks or burrs, and close inspection of the scope mounts is in order here. I used to have the cheap, aluminum see through mounts on my 742, hoping I could use iron sights if I was too close for a scope. Never had cause to use them, and when I got old enough to give up on iron sights I replaced the mounts with solid steel Leupold mounts. I was shocked to find that the screws that I had so diligently tightened at installation had loosened up over time. The new Leupold mounts are lower, came with Torx screws and are Loctited in place. The rifle LOOKS better now too as well as points better.

I'd also recommend trying several different loads; mine is REALLY picky, seems to work best with one particular factory load, never even liked any of my handlaods that much.

Good luck - - there's worse fun to be had than troubleshooting an accuracy problem (for awhile at least!)Keep us posted as to how things are going!

[mistahmojoryan]

I took my 742 in 30/06 out last year and it was printing 3-3.5" groups at 100m. I think that's decent for the 742. If it didn't jam all the time I would've worked with it a bit cause it was a great brush gun.

[camp_13]

Ok, Got a new scope on the 742, a 3-9X40 Swift (really nice scope for $129) and I gave the barrel a good scrubbing to boot, here is my new group at 100 yards, now thats more like it!!