Can't make the 1/2 inch 50 yard challenge and need help to do so

Never seen one of these rifles in the flesh but if press fit.... proper fitting mandrel, a bit of heat, a hydraulic press

use the original barrel to measure up the replacement.... heat, press. voila.

Jerry
 
One more thought now that you've posted the rifle's trigger pull weight at 20 ounces.

In the first post, it's indicated that you are shooting free recoil style. This can be a challenge with a rifle such as the M70/77, which both share the same stock, because of the rounded forestock. More importantly, it can be even more challenging with a trigger pull of 20 ounces. That's heavy for free recoil shooting. Many shooters who use the free recoil method use triggers with pull weights as low as possible, which means under 5 ounces.

When I had M70/77 rifles, several with upgraded triggers as shown below, I shot them with a firm grip. I don't recall what the trigger pulls were, but they didn't inspire confidence in free recoil shooting.

 
Mystic Precision said:
Never seen one of these rifles in the flesh but if press fit.... proper fitting mandrel, a bit of heat, a hydraulic press

use the original barrel to measure up the replacement.... heat, press. voila.

Jerry
Click to expand...

Replacing a factory barrel on a S&L M70/77 with a custom barrel may not be worth the cost and effort. This is a very basic rifle, designed for cost effective club shooting. It doesn't even have an ejector. More serious S&L shooters used the "free rifle" models that usually had a thumbhole stock. These too had no ejectors, but were equipped with very nice double set triggers with very low pull weights indeed.
 
jamesharrison said:
Re: sporter-barrelled rifles
Would that include a barrel with a muzzle diameter of 0.850” at the 26.75” mark?
I’ll think on the gasket maker bedding pad this winter. What are your thoughts on simply cutting & using a piece of bicycle inner tube as a stop-gap measure to see if the added pressure works?
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Yeah, that's a fairly long barrel. I've got a 24" straight 0.850" barrel and it'll string 3/4' vertical with ammo it doesn't like. Oh for sure the bicycle inner tube would be easier/quicker to try, members on RFC have reported very good results with it so by all means give that a go before investing the time and effort into bedding with the gasket compound. Heck, maybe you'll be fine with just the bike tube!

I see you say you only clean about once a year, that could be a factor as well. I had an old Walther KKJ-T that needed to be squeaky clean to do 1/2", and I had about a 75 shot window to do it before it started opening up.
 
Well, some progress, I guess.

Bought a 36x B&L and a borescope. Hopefully, the increased resolution should help, as long as the mirage isn't too bad. The borescope may be another problem solved, or discovered, depending on what I find!

Thank you Steve (sfp)

Now for the bad news. Tried to buy a Sinclair forend benchrest adapter & it's sold out with no back-orders, so perhaps it's been discontinued. Trying to find something similar.
 
jamesharrison said:
Well, some progress, I guess.

Bought a 36x B&L and a borescope. Hopefully, the increased resolution should help, as long as the mirage isn't too bad.

Now for the bad news. Tried to buy a Sinclair forend benchrest adapter & it's sold out with no back-orders, so perhaps it's been discontinued. Trying to find something similar.
Click to expand...

The resolution with the B&L 36X scope may not be increased but the magnification will be greater. These are nice scopes. I've had two of them and liked them a great deal.

I have a Sinclair forend benchrest adapter that I won't be using in the future. Let me know if you're interested.

 
Oldly said:
Your a snow bird
Click to expand...

Nope; it's just that me & the ice have an agreement: I stay off it & it doesn't go out from underneath me & if you want to travel in the Whiteshell in winter, you're going to have to go on solid water. Back in '86, I went through the ice when I was caribou hunting on Boxing Day when I lived in Yellowknife. That's not an experience I want to go through again. That plus the fact that I spent quite a few years in very hot, very dry $#!TE-holes around the world when I was a younger man & the cold just seems to go through me nowadays.
 
Although my recently-acquired borescope has not yet arrived I must, with some chagrin, report my shame in front of you all.

:-(

After removing the bolt retaining screw and bolt, and swabbing the chamber & part of the bore with Wipe-Out Carb-Out, the amount of brown grunge coming out of there was despicable! While I could not detect a carbon "Ring" per-se, I did notice quite the build-up of "stuff" just in front of the leade. Repeated the exercise, followed with wipings of Kroil, then dry patches, then Wipe-Out Patch-Out, dry patches. I repeated the Carb-Out/Kroil/Patch-Out routine several times over 24 hours. The bore & chamber finally appear to be clean, which I will confirm once the borescope gets here.

Unfortunately, no range test for awhile, as it is currently -27 with the windchill here in Winterpeg.

I think, however, that prior to adding a piece of bicycle tube to the bedding, I will re-confirm some groups (I hate adding more than 1 variable at a time when I am testing something), following which I hope to join the 1/2" club.

I'll post some photos here once I receive the borescope & can figure out the photo down-loading procedure.

In the meantime, THANK YOU all for the advice.
 
james, good that you're getting a borescope. As for the carbon ring, it may be that some has worn/chipped away. I've read that when it 'warms up' from firing, it becomes malleable and may wear off a bit. Some may remain to collect more. While I'm brushing my bore, I take the brush and spin it in the chamber area with Carbon solvent - seems to work for me. Copper solvent will be needed when you are firing a FMJ caliber, the .22s except for Mag generally don't have copper clad. The 'gold-looking' stuff is gilding which mostly won't build up, I beieve.
 
If you want to achieve the best accuracy, don't worry about a rim thickness gauge unless the intention is to shoot bulk or other inexpensive ammo, in which case it might help a little.

Focus instead on getting the most appropriate ammo for your rifle. Use match ammo, and test it. Not all such ammo, regardless of the name on the box, performs equally. There are no shortcuts, no devices that will make the rifle/ammo combination shoot better.

In any case, good quality ammo typically has insignificant variation in rim thickness. Although sorting ammo by rim thickness was once popular like a fad, today few, if any, serious rimfire shooters sort ammo by any mechanical means.
 
When I found that a 22 long rifle would fall in to the mouth of a 243 Win case, I trimmed it to square, chamfered the inside of the neck and used a caliper to measure the length.

Just as accurate as my Bald Eagle but the eagle is faster.

But i agree with Glenn. Nothing beats testing and finding the best ammo for your rifle.
 
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