I recently purchased a pre-18 expecting similar accuracy as a
no dash-18, but it is not measuring up.

What are some things I can do to improve the accuracy of the gun? Should I try different ammo? The barrel looks fine, no leading, but could a thorough cleaning help out? It has a very tight barrel-cylinder gap, 0.0025", can that have an effect? Otherwise, timing and lockup are excellent.

Thanks for any advice.

Hey, Pete. Check that cylinder gap again. 1/4" is a heck of a lot!!!

Try a different brand of ammo. 22s can vary quite a bit with different ammo.

Since it is new-to-you, I would start with a thorough cleaning of both barrel and cylinder and then test with several different .22 cartridges. If the cylinder is really crudded-up, you may have to leave some Hoppe's-soaked patches in it (at the front end of each of the chambers and exit bores) for a couple hours, scrub with bronze brush, and repeat the process several times. Assuming you have checked your barrel for any signs of damage... ? (rings, nick in crown, etc.)

Good advise so far! I have a M-18-3 that I had about given up on after trying many different brands of ammo, standard velocity, hi speed, target ammo you name it and the dang thing just dident like any of it. Untill I got around to trying Winchester X-pert bulk box ammo in it, presto chango into a very accurate revolver. You never know about 22's, some will eat anything and some are just fussy, keep trying with your's, good luck!

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Hey OFTII, check your decimal tables again ! .0025" is somewhat less than a quarter inch.

Larry

I just moved the decimal point! OFTII noted the mistake correctly.

I'll give the gun a good cleaning and then try a few different brands of ammo.

I have a couple dedicated rimfire-shooting friends who are big advocates of carefully cleaning the bore with JB. They claim it frequently improves accuracy. I am not a big rimfire shooter and do not have any firsthand experience with this. I did buy a jar to give it a try, but so far the jar is still sitting there. Anyway, that might be something else you would benefit from investigating.

JB Bore Paste is wonderful stuff . For lead bullets you want a smooth polished bore . Rimfire guns are notoriously ammo finicky . As a 2700 shooter & owner of 12 22 target pistols I can tell you that all perform their best with different ammo . Needless to say keeping that many different lots / mfgers is not cost effective . In my case all perform well enough with CCI Std Vel that's what I buy . When you start on 22 rifles it gets worse in terms of finicky . Since we're talking a 4" barrel here I doubt you're concerned with 50yd groups . I'd pick up 100 rounds of every kind of 22 ammo you can afford & shoot off a sandbag rest or Ransom rest @ your usual distance . I'm sure you'll find one or more that perform well enough . I'd start with an absolutely clean barrel shoot 20 rounds to foul it , then start shooting groups . Also clean well again before trying a different ammo . Lube from previous will affect group size . Take your time paying strict attention to sight alignment & trigger control . Also make sure you aim @ same spot on the target each time . Not easy to do with open sights , especially with older eyes .

Lots of good info here, but I would elaborate on checking the muzzle. Just a tiny nick can disrupt your accuracy. The .0025" B/C gap contributes to accuracy, (but be sure to keep the front of the cylinder clean). When trying the different types of ammo, be sure to shoot off the bench rest, and do not rest the barrel on anything. Only rest the frame and front of the trigger guard against the sandbag. Resting the barrel can definitely hurt accuracy. If possible, test with a Ransom Rest. With revolvers, my experience has been overly waxy bullet lube does not help accuracy. I am sure you know that the shorter sighting radius causes greater sighting error, and calls for more concentration when shooting shorter barrels.

Similar to Vulcan Bob, I found my Pre 18 shot best with Fed. bulk box ammo. My 17-4 doesn't like it at all.

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H Richard
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