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Discussion Starter #1
A couple of months ago I bought a 39A--ser. no. Lxxx at a gun show and brought it back to life with a new firing pin, buttplate, and a good cleaning. I wanted to mount a period-correct scope and did so with a Weaver K4 that I bought at the big Reno show last month. Well, I tested it at the range today with samples of a half dozen ammo brands and types and couldn't get a decent group with any of them. I was shooting at 10 meter air pistol targets at 50 yds--the target has a black bull of about 2 1/4" and the only ammo I had which would stay in the black was some old Remington Pistol Match. Some of the other ammo samples were admittedly cheap stuff like Remington Thunderbolt and some Federal Hi-Power but I also shot 20 rounds of RWS Target and it didn't do any better. I have several others to try and I should have held off on this posting until I do but thought I might get some input first. I should add that I can see no damage to the muzzle of the gun or anything else that is obvious. The gun has pre-Micro- Groove rifling.
 

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There are so many variables, it's hard to say. My suggestion -- get someone else who is a skilled shooter to shoot it first. The main reason I say this is not to disparage your abilities; rather, you could be experiencing nothing more than an inconsistent cheek weld on the stock, leading to parallax error with that K4 scope. I always look at changing myself before I look at changing anything on a gun, unless a particular problem jumps out at me.
 

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I recently acquired a Marlin 39 TDS in near-new condition, and initial range testing with several types/brands of ammo at 50 yards with the issue iron sights was dismal to abysmal, as groups ranged from 3-5+ inches! After two such range sessions, and with two other shooters behind the trigger I'd had enough!

I ran 36 CB Long fire-lapping loads through the little lever, polished the bore as per the Beartooth Tech Guide lapping procedure, then fired for groups.

First group at 50 yards post lapping using Federal bulk-pack HP's (Wally World specials) resulted in sub 1" for five shots with the miserable issue sights. Subsequent groups were similar, notably better shooting near 5/8" with Remington ammo.

Your mileage might vary, but it's perhaps worth consideration if groups don't tighten up otherwise.
 

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I would take a very hard look at that scope - even to the point of replacing it with another of known reliability - because that rifle ought to do much better.

My peep-sighted "L" prefix 39a can stay under a US Dime @ 50yds, provided I do my part.

.
 

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I would remove the scope and try it with open sights. Also, soak the bore with some Hoppe's #9 or similar lead removing cleaner for awhile, then clean thoroughly. You may have an accumulation of lead in the bore. Removing the scope will remove a big variable. The scope may be moving in the mounts, or the crosshairs may be shifting in an old scope like that.
 

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Discussion Starter #6
I forgot to mention that I shot it with the iron sights at 50' before mounting the scope and got 3/4 to 1" groups. The scope is rock solid in the (Burris) rings on the mount--I suppose the scope could be suspect but it appears to have had very little use and optically is quite good. Tried the gun again yesterday at 50 yds. with samples of good (not premium) ammo--Wolf Match Target, Lapua blue box Std. Vel., Lapua red box Super Match--3"" + groups again. Will have my gunsmith buddy examine the barrel crown and possibly re-crown it. Thanks Marshall for your suggestion of fire lapping, but another friend--a longtime shooter-machinist--said that ought to be a last resort. Thanks all for your input.
 

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Pete, let me see, You can shoot 3/4" to 1" groups with the iron sights, and only 2.5" to 3" groups with an old scope and you're looking at the crown? Remove that scope and replace it with one of known performance. Clear it may be, but it may still have loose crosshairs, leading to a wandering point-of-impact.
Or try it with the scope at the same 50'. No way should your groups be worse with the scope. Unless the scope is bad.

Good luck.
 

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The guys are right Pete. I date back to an era where Lyman
"K" scopes were the most easily attainable and the most
inexpensive scopes to buy. Some were O.K. others were
not worth a dime. Do what they are telling you and try another
scope on that Marlin.

Zeke
 

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The Hog Whisperer (Administrator)
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Yeah, I think you have a scope problem. Iron sights outshooting a scope by that much ought to tell you something....

Lapping isn't a bad idea, in any case. Doesn't have to be a 'last resort'.
 

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Discussion Starter #10
Disappointing groups

If you guys would read more carefully you might realize that 1 in. groups at fifty FEET are comparable to 3 in. groups at fifty YARDS. C'mon--give me a little credit. I'm not ungrateful for well-meaning help, really. I'll try it next with a target-type Williams receiver sight as soon as I receive a front block (or order) to mount a Lyman 93 globe front. My intention was to shoot some rimfire cowboy silouette matches.
 

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The Hog Whisperer (Administrator)
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I did miss the units, sorry!

I would still lap it. Easy and it isn't going to hurt the barrel. Let us know if you get different results with the peep sight.
 

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1" at 50 feet equals 3" at 50 yards, yes -- with the same sights. But at least for me, that 3" iron-sighted at 50 yards would normally be no more than half that with a scope. Granted, that's just me. But if it WERE me and my rifle, I would definitely swap off the scope and try one of known reliability before looking at other factors.
 

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Nawth East Moderatah
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Perplexing,
As
I too have an old 39, a 'mountie' form the early 50's.

While it is not scoped, it WILL hit anything you aim it at, no matter the ammo.

when I got it, it was crudded, in and out. I used the takedown screw, took it apart, and plugged the muzzle. Filled it with hoppes and let it stay for a week.
What drained out was this primeval guuk....A good scrubbing with a brass bore brush, plenty of patches in between, and a shiny bore appeared.

Do make sure your takedown screw is tight too....not over tight, but tight!

I'm gonna go with the scope too, reason being many moons ago I had a K4 on a Win 100. The scope went south, and ended up being sent to el -paso for repair. The Cross hairs do loosten on the old K series.
 

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Nawth East Moderatah
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Marshall;

Are you now offering pre-loaded .22LR ammo for lapping, or did you just embed the .22 ammo?
 

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If you guys would read more carefully you might realize that 1 in. groups at fifty FEET are comparable to 3 in. groups at fifty YARDS. C'mon--give me a little credit. I'm not ungrateful for well-meaning help, really. I'll try it next with a target-type Williams receiver sight as soon as I receive a front block (or order) to mount a Lyman 93 globe front. My intention was to shoot some rimfire cowboy silouette matches.
Pete, you been around here long enough, and have contributed enough so I do trust what you say. However, I would still do a comparison at 25 yards with and without the scope. Either swap it out for another scope you trust or use open or peep sights. I still think the crosshairs in that scope COULD be moving. I also still think you should soak the bore, like I suggested before, and like Chris said, in Hoppe's # 9 to remove lead. I would certainly look hard at the crown, but I would not suspect it unless I could see something wrong with it upon close inspection.
I have and/or had close to a dozen 39's, and have never had a damaged crown, but I have had lead buildup and I have seen a bore that was pitted bad enough to keep the gun from grouping.
To me, when I do a comparative test to find the cause of poor groups, I make sure only ONE variable is changed at a time, with everything else remaining the same so I know without a doubt what the culprit is. That's all we're trying to say.
I hope that helps, and best of luck to you. Please let us know what you find!
 

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The cleaning idea has appeal to me, as well. A lot of folks never clean their .22's, trusting the bullet lube to protect the bore. How well that works can depend on the humidity where you live.

Hoppes is not a lead solvent, but it will eventually penetrate the carbon that is deposited between lead layers. It's a decent nitro powder solvent. Ed's Red is cheaper and better as a powder solvent, IMHO, but may not be as good a penetrant? I don't know on that score? One thing that is definitely able to soften hardened carbon as well as get nitro residue and penetrate and loosen rust and lead is Gunzilla. It is vegetable oil based, so it is safe and easy on your skin. It works amazingly well. But if you're going to leave it for a week, most things will probably help. Kroil penetrating oil is another good choice for that kind of long soak.

Sharpshoot-R, makers of Wipe Out, now have a product called Wipe Out No-Lead that is a true lead solvent, if you want to try that?

Once you get it cleaned out, see if any of your friends has a Hawkeye Borescope? That will let you see what shape the bore really is in? That will give you a basis for deciding on firelapping? If there are any sharp edged pits, it is likely to be a good idea.
 

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Make sure there isn't a bunch of lead in the barrel....

+1

BTW - Loose crosshairs are not the only possibility.

Quite often the lens seating gives up the ghost, allowing one/more of the internal lenses to slightly shift under recoil (as little as it may seem), tossing consistancy in the crapper.




.
 

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I would remove the scope and try it with open sights. Also, soak the bore with some Hoppe's #9 or similar lead removing cleaner for awhile, then clean thoroughly. You may have an accumulation of lead in the bore. Removing the scope will remove a big variable. The scope may be moving in the mounts, or the crosshairs may be shifting in an old scope like that.
I've had a used scope be the cause of poor groups. I had mounted a used Simmons scope on Browning pump 22 rifle. With scope on I got 4 inch group at 25 yards. with it's iron sights I could shoot 2 inch group. with new scope, also a Simmons, quater sized all day long.

I have a Lyman receiver sight on my Marlin 39A. With that set up. my old eyes give me 2 inch groups at 50 yards, if I do my part.
 

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Tater,

A lot of new users peruse the posts and don't think to look at the date. You're responding to a question asked and answered 2½ years ago. It's what we call a zombie thread when it's this old and "brought back to life". Since the original participants have long since got their answer or lost interest, the only reason to revive something this old is if you have an entirely new theory or answer or suggestion. In that case you probably want to say "I know this thread is old, but here's another {idea; solution; etc.} for anyone else having this problem. Simply confirming an earlier suggestion doesn't really qualify.
 
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