Can Removing Cocking Arm vibration/looseness improve Accuracy?
Okay, I’m a rank amateur so take what I say with a grain of salt. I bought a Diana 430L and love it, but I’ve been struggling with moments of fantastic accuracy, followed by moments where POI was drifting off. My first problem was a breech seal failure which I fixed after making a spring compressor. Next, I noticed my Hawke 2-7x scope sliding on the rail, so I made a stop pin for my low budget drooper scope mount which seems to have cured that problem (fingers crossed). But most recently, I noticed times where my groups would be good for a while then they would start to open up significantly and start going high. The shot cycle would feel strange during these instances. I also noticed that this was usually accompanied by the cocking arm coming unsnapped from its locked position and hanging loose after the shot. I wasn’t sure if the accuracy problem / feel was caused by a rough shot cycle or the cocking arm coming loose, but I decided I’d attack the loose cocking arm first since it was easier. My first targets were shot at 17 yards since I was trying to get consistent at that distance before pushing out farther. Photo #1 shows an example of the groups opening up at times. Group numbers 4 & 5 had rougher shot cycles than usual and I would find that the cocking arm had fallen loose from its closed position after the shot. I ultimately decided to put a little rubber bumper (like used on cabinets to help them close quietly) on the rifle’s nose piece as shown in photo #2. This bumper puts a little tension on the cocking arm locking mechanism so the arm is no longer loose. So far it seems to be working to keep the cocking arm in place. Photo #3 shows another set of 50 shots, with much less stringing, and at no time did the cocking arm fall lose. Finally in Photo #4 I pushed things out to 25 yards to try Oldspooks 10 dimes challenge. I failed on my first two attempts at the challenge due to wind and a lack of concentration, but this third attempt sort of panned out. Groups 8 & 9 opened up more than I had hoped, but overall I’ll take it. I used Oldspooks 1st generation target (works better with my setup), but I only shot 3 pellets at each spot per the 2nd generation target rules (pretty sure I wouldn’t have made it with 5 shots). I’m still struggling a bit with slight POI shift, but nothing like the stringing I was seeing before I put the rubber bump stop on the barrel. This slight POI shift may be scope or mount related, or more likely, just me not being consistent enough in hold. For example, on my first shot I nearly dropped one completely out, so I had to start aiming a little left of center. By the way, this is all shot off of a shooting bag without artillery hold, as I don’t have the skill/steadiness to do this free hand.
Anyhow, you might try experimenting with a little something like a rubber bumper to hold tension on the cocking arm so it doesn’t rattle around during the shot cycle. It seems to be working for me, or, it may just be the placebo effect. Either way, I’ll take it. Love this 430L, as I’m getting things ironed out, I never get the dreaded flyer that lands an inch away from where I aimed.
Photo 1: Shot at 17 yards. Groups 4 & 5 start opening up and these are times where I found the cocking arm had fallen loose from its locked position.
Photo2: Rubber bumper installed which helps hold the cocking arm stable during the shot cycle
Photo 3: Shot at 17 yards after the rubber bumper fix. Groups stay tighter overall. Ignore Bull #4 as I was adjusting the scope – and started off in the wrong direction.
Photo4: Shot at 25 yards. Version 1 of 10 dimes challenge but with 3 shots per bull. Actually hitting dime size targets adds a layer of difficulty over getting dime size groups.
Okay, I’m a rank amateur so take what I say with a grain of salt. I bought a Diana 430L and love it, but I’ve been struggling with moments of fantastic accuracy, followed by moments where POI was drifting off. My first problem was a breech seal failure which I fixed after making a spring compressor. Next, I noticed my Hawke 2-7x scope sliding on the rail, so I made a stop pin for my low budget drooper scope mount which seems to have cured that problem (fingers crossed). But most recently, I noticed times where my groups would be good for a while then they would start to open up significantly and start going high. The shot cycle would feel strange during these instances. I also noticed that this was usually accompanied by the cocking arm coming unsnapped from its locked position and hanging loose after the shot. I wasn’t sure if the accuracy problem / feel was caused by a rough shot cycle or the cocking arm coming loose, but I decided I’d attack the loose cocking arm first since it was easier. My first targets were shot at 17 yards since I was trying to get consistent at that distance before pushing out farther. Photo #1 shows an example of the groups opening up at times. Group numbers 4 & 5 had rougher shot cycles than usual and I would find that the cocking arm had fallen loose from its closed position after the shot. I ultimately decided to put a little rubber bumper (like used on cabinets to help them close quietly) on the rifle’s nose piece as shown in photo #2. This bumper puts a little tension on the cocking arm locking mechanism so the arm is no longer loose. So far it seems to be working to keep the cocking arm in place. Photo #3 shows another set of 50 shots, with much less stringing, and at no time did the cocking arm fall lose. Finally in Photo #4 I pushed things out to 25 yards to try Oldspooks 10 dimes challenge. I failed on my first two attempts at the challenge due to wind and a lack of concentration, but this third attempt sort of panned out. Groups 8 & 9 opened up more than I had hoped, but overall I’ll take it. I used Oldspooks 1st generation target (works better with my setup), but I only shot 3 pellets at each spot per the 2nd generation target rules (pretty sure I wouldn’t have made it with 5 shots). I’m still struggling a bit with slight POI shift, but nothing like the stringing I was seeing before I put the rubber bump stop on the barrel. This slight POI shift may be scope or mount related, or more likely, just me not being consistent enough in hold. For example, on my first shot I nearly dropped one completely out, so I had to start aiming a little left of center. By the way, this is all shot off of a shooting bag without artillery hold, as I don’t have the skill/steadiness to do this free hand.
Anyhow, you might try experimenting with a little something like a rubber bumper to hold tension on the cocking arm so it doesn’t rattle around during the shot cycle. It seems to be working for me, or, it may just be the placebo effect. Either way, I’ll take it. Love this 430L, as I’m getting things ironed out, I never get the dreaded flyer that lands an inch away from where I aimed.
Photo 1: Shot at 17 yards. Groups 4 & 5 start opening up and these are times where I found the cocking arm had fallen loose from its locked position.
Photo2: Rubber bumper installed which helps hold the cocking arm stable during the shot cycle
Photo 3: Shot at 17 yards after the rubber bumper fix. Groups stay tighter overall. Ignore Bull #4 as I was adjusting the scope – and started off in the wrong direction.
Photo4: Shot at 25 yards. Version 1 of 10 dimes challenge but with 3 shots per bull. Actually hitting dime size targets adds a layer of difficulty over getting dime size groups.