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Tuning How to break your Impact

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Khornet

Khornet

Member
Feb 10, 2020
194
5
NH, United States
MkII, .22, 700 mm, Power Plenum. Generally shooting 23 grain H&N .218 slugs at 900-910 fps with regulator at 95-100 bar. I have a bad habit of opening the action and inserting a slug in the single-loader, then checking my reticle or level and forgetting to close the breech before firing. The loading block slams forward, and the cocking lever snaps forward and raps my knuckles. I've examined the cocking pin on the loading block, and the hammer has not peened or bent it. Likewise the hammer shows no injury, though in 9 months of use I've probably done this 50 times.

Did it one time too many about 10 days ago. Heard a loud pop and a metal part flew off the rifle. That was the sidelever linkage. The sidelever had failed at the pin hole which links it to the linkage.

Found the linkage and disassemble the rifle. The rear hole of the linkage had become elongated and deformed, but again nothing else was bent, deformed, or peened. Ordered up a new lever, linkage, and related pins. They arrived yesterday. New lever does not have the bronze bushing in its rear hole but it fits its pin fine. Rear hole of linkage fits its pin fine. FRONT hole of linkage is much too small for its pin; pin is about 0.10". Original linkage had holes of identical size, not two different sizes. Carefully drilled out the hole to fit, reassembled and tested, and rifle is back in action and shooting as well as before.

But enlarging the front hole in the linkage does not leave a lot of metal, and I bet it will wear prematurely even though I've learned my lesson about closing the breech. Have the specs of the cocking lever and linkage changed? I thought I read that the pins in the reloading block had been beefed up because of people like me. Maybe the replacement linkage was old-style?
20210112_124203.1610896844.jpg
20210108_100341.1610896859.jpg

 
For a while before the failure I was having accuracy problems and shifting zero (though I think the latter is scope-related), and I was feeling a slap from the cocking lever when firing. Probably because lockup was not complete because of the elongated hole. Now there is no slap, and accuracy seems back to normal though it's too windy to be sure. I let FX USA know, and asked about different versions of the linkage.
 
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Khornet, I have done that myself on different guns. One really feels like an idiot after it happens; it's the proverbial "dOh" moment. Fortunately, no damage. It always happened when I was busy with details of the shot, just as you mentioned. After making a conscious decision to be a bit more careful about it, it has not happened again :)
 
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Actually, I'm a lefty. In my quest for max accuracy I got a single-loading mag early on, and I think the extra steps (pull lever, open loader, insert slug, close loader) can set you up to forget a step in your excitement. In any case, the point was to show one of the kinds of failure which can result from that error. Also to note that it caused variations in depth of pellet seating, which I suspect was part of my zero shifting and accuracy problem. And therefore one should consider whether that hole in the linkage could also develop from normal wear, so if your accuracy has gone south, take a look at the holes in the lever and linkage.
 
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Corvid hunter, in the fall I was getting about 75-100 shots from 200 bar to 100 bar. Now shooting in 25-30 degrees it looks more like 50.
Click to expand...

Great lesson I’ve learned from this thread. Shouldn’t be too bad of a fix for you though $$$ wise. Have you requested the parts from FX USA yet?
You really think the weather has that much of an impact on your shot count? I haven’t had my Impact long enough to know, it’s been freezing since it arrived. My marauder doesn’t seem phased by the cold weather that much. 
 
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It was not an expensive fix, ordered and installed the parts and back in action. Chrono shooting in my basement at 64 degrees I seem to be getting that many shots, but outside it's been 20-30 degrees and it does seem significantly less. But I haven't actually counted in either place, just an impression. If I remember to count I'll let you know. Busy now remembering to close the breech.
 
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Hobbyist, I'd love to make my own part, but do not have the equipment right now. Could ask a machinist, I guess. Meanwhile I've learned a couple of new things:

1. Some Crown parts have the same number as their Impact counterparts. My replacement cocking lever lacked the brass or bronze bushing for the pin which attaches it to the rear block. You can just see that bushing in the pic of the broken lever in place on the rifle. Also, it wouldn't quite fit the slot in the original handle, and requires a little work with a fine stone. Turns out it is a Crown lever, which has the same number as the Impact part, that's why. Works fine, though.

2. The replacement linkage has holes of two different sizes, with the front hole which engages the pin on the loading block being smaller than the original. I enlarged it carefully, and installed, and it works fine. Turns out there is a variation, and the drawing shows part 19021 while the original part on my rifle is 19021-1.

The folks at FX-USA were very patient in helping me figure this out, and a second set of parts is on the way. Meanwhile, shooting with the "wrong" parts, I've shot several sub-MOA 5 shot groups at 100 yd in the last 2 days.
 
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