How Can I Fix Vertical Stringing?

Improving and repairing firearms. Rifle bedding, barrel work, stock replacement and other ways to improve your firearms.

Re: How Can I Fix Vertical Stringing?

Post by Wm.Traynor » 19 Nov 2018, 9:04 pm

2018-11-19 16.41.28.jpg
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This is that pesky screw. At the flat, smooth-turned, tip you can make out a "bevel". I wonder if this has been formed/deformed by colliding with the forward edge of the hole? Well, that's my theory................for now ;)
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Re: How Can I Fix Vertical Stringing?

Post by Wm.Traynor » 19 Nov 2018, 9:13 pm

2018-11-19 16.40.51.jpg
A slightly better view of the "bevel", which is at six o'clock on the flat tip.
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Re: How Can I Fix Vertical Stringing?

Post by Wm.Traynor » 19 Nov 2018, 9:25 pm

The question now remains as to what to do to stop the tube sliding forward. I'll have to think about that but a screw of the right length comes to mind. I wonder if this is a stock screw or a bodgey one and what would they send me if I ordered a new one?
Oh dear, I think I'm starting to lose my marbles :? :crazy:
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Re: How Can I Fix Vertical Stringing?

Post by marksman » 20 Nov 2018, 6:28 pm

I think your approach is very logical
IMHO I do not think this is your problem causing the vertical stringing but I would want the rifle to be solid as you do
it actually sounds to me like the temper of the barrel is not good causing the barrel to warp as it heats up :unknown:
I would try shoot a group very slowly giving a big amount of time between shots to shoot from a cold barrel each shot and see if the vertical is still there
good luck with it anyway :thumbsup:
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Re: How Can I Fix Vertical Stringing?

Post by Wm.Traynor » 20 Nov 2018, 7:15 pm

Thanks for your reply marksman :thumbsup:
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Re: How Can I Fix Vertical Stringing?

Post by Wm.Traynor » 20 Nov 2018, 7:39 pm

At this point, I have only questions. For instance, "What is the proper function of the Magazine Cap Screw?" We know that it holds the cap secure in the tube but the length of unthreaded, turned-down section could have two functions, namely 1) to stop the tube sliding and 2) to apply pressure to the underside of the barrel, as a means of "tuning" the vertical spread. My MCS performs neither function because contact is haphazard, random and unreliable.

And then there is marksman's point about a warping barrel but to test that idea the tube has to stop creeping. Did I mention that the tube can be moved backwards and forwards when the front barrel band (FBB )is tightened firmly? There are cut-outs in the bottom of the barrel and top of the tube for the screw but this fastener does not make enough contact with the mag tube to prevent movement. I am thinking of packing the bottom of the lower half of the band which will raise the whole tube. This will make the MCS fit inside the blind barrel hole. That way both the MCS and the FBB will prevent sliding...............I hope ;)
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Re: How Can I Fix Vertical Stringing?

Post by Wm.Traynor » 20 Feb 2020, 3:07 pm

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Re: How Can I Fix Vertical Stringing?

Post by Wm.Traynor » 20 Feb 2020, 3:41 pm

As you can see from the pic above, pasting with comments is something that I have not mastered HOWEVER, I have fixed this freaking damn gun :D :D :D

Much of the credit must go to In2anity who posted his work on a Marlin 336. His reference to the book by M L McPherson was invaluable, in the end. By that, I mean that bedding my fore end in RTV did not work at all, in reducing vertical stringing. It should be said right here, that all of the mods performed by me over the years might not have acted in my best interests. Yes, this is damn complicated. To simplify, In2anity's fix might have worked had I not hollowed out the fore end, relieved the barrel channel, yada, yada, etc.
To cut a long story :( :crazy: short, after failing initially with the RTV, I went the Whole Hog with McPherson's Method and added the RTV between the front and rear barrel bands and ran a bead of it between mag tube and barrel, from action to muzzle.
THAT made a Very Big improvement immediately. The mag tube stayed in place :thumbsup: That's a plus, eh?! :D
The above pic does not reflect that huge leap, from 6" to about 2". This pic above was of last Saturday's testing at 50 yards where I tried to reduce the string further. Shots 1,2 and 3 were fired with the Rear Barrel Band Screw in the same position (firm but not Really Tight) as it was last month, 24/1/20. The rifle grouped about the same; no surprises there.
Shots 4,5 and 6 were fired after the FRONT barrel band screw was slackened by 1/4 turn. Still plenty of vertical. The rifle was being cooled between 3 shot groups so the barrel would not heat up too much.
Shots 7,8 and 9 were much better from the point of view of string. I blame #9 on the terrible trigger. The rifle cooled during a target change and 10 and 11 were fired. That was the end of the ammo. The group 7 to 11 is only about 1.25" deep. That will do me :D :D :D
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Re: How Can I Fix Vertical Stringing?

Post by Oldbloke » 20 Feb 2020, 3:59 pm

WM. Posted the target for you.


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Re: How Can I Fix Vertical Stringing?

Post by Wm.Traynor » 20 Feb 2020, 5:02 pm

Thanks Oldbloke. I was sure it worked for me :problem: I will double check next time but in the meantime, would you mind telling me how you fixed it please?
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Re: How Can I Fix Vertical Stringing?

Post by Oldbloke » 20 Feb 2020, 5:23 pm

WM. Just go to forum help."how to upload pics

Try this link

viewtopic.php?f=27&t=1011
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Re: How Can I Fix Vertical Stringing?

Post by marksman » 21 Feb 2020, 10:43 am

good on you, good news :drinks:
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Re: How Can I Fix Vertical Stringing?

Post by Wm.Traynor » 21 Feb 2020, 11:35 am

Thanks marksman :D :thumbsup:
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