Vertical Stringing?

[ab_bentley]

So my beloved 22BR is giving me fits. It's stringing in the worst way. I have shot proven loads through it and it's just putting them straight up and down. Screws are tight, bench etiquette is on point, primers are proven. I just crested 300rds through the barrel.

I thought it was the crown, so I re-crowned it, thought it was dirty and I cleaned it. It literally just stopped shooting today, except in vertical form.



Adam

 

[LHSmith]

Powder charge too high or low for given conditions. Front bag too hard....massage it, needs wider mirage shield,

 

[LHSmith]

Shooting N-133? aka vertical-vouri when using below 30% RH.

 

[ab_bentley]

That's what I thought, but this is with proven accurate loads. I even backed off the powder and it still would string. I was using Varget and RL15, both proven ultra accurate loads.

Adam

 

[hogpatrol]

What make of barrel? Maybe the throat is eroding faster than normal?

 

[MrMajestic]

AB, do you think the weight of that truck axle changed/affected something adversely? Just brainstorming...

 

[LHSmith]

That's what I thought, but this is with proven accurate loads. I even backed off the powder and it still would string. I was using Varget and RL15, both proven ultra accurate loads.

Adam

Any reason you couldn't go up in charge? Have you shot those proven loads in these temps before?

 

[ab_bentley]

What make of barrel? Maybe the throat is eroding faster than normal?

I think this is the answer. I blew primers at 30.8gr of RL15 when it was new, today I went to 31.8gr with no pressure witch leads me to believe that there is a loose spot, I.e. missing throat/ eroded throat. I'm going to jb bore paste it and slug the barrel tomorrow.

This is the new X-caliber barrel 3 groove.



It would consistently do this a week ago.

Adam

 

[LHSmith]

I checked my notes-other possibilities: 1/seat depth engrave into lands more aggressively (throat more worn?), 2/increase neck tension, 3/front bag not slippery, 4/ change position of fore-end on front rest. Also check bullet holes- oblong = charge too low.

 

[ab_bentley]

I checked my notes-other possibilities: 1/seat depth engrave into lands more aggressively (throat more worn?), 2/increase neck tension, 3/front bag not slippery, 4/ change position of fore-end on front rest. Also check bullet holes- oblong = charge too low.

My trigger pin walked out, just noticed it. I'm betting that is the cause. If you look at the grouping, it's almost perfectly vertical in most cases which screams accuracy. The loose trigger will effect the pin fall, their effecting groups. I'm almost positive the loose trigger is the problem.

Adam

 

[338 Mollett]

Best 500yd. groups I've ever seen?

 

[Hummer]

You could have a striker string giving marginal ignition energy. What does your chronograph say regarding SD/ES for your loads?

Also something may have changed and the barrel is walking as it heats up which I have had happen.

 

[ab_bentley]

You could have a striker string giving marginal ignition energy. What does your chronograph say regarding SD/ES for your loads?

Also something may have changed and the barrel is walking as it heats up which I have had happen.

I'll put money on the trigger being loose is what's causing that. I've run the barrel enough to know it's something new.

Adam

 

[Lapua40X]

... I have shot proven loads through it and it's just putting them straight up and down....
Adam

Proven loads aren't "proven" until they've been proven in the rifle your loading them in.
If they've proven accurate in this rifle in the past I'd look for shooter input issues; among them would be rear bag and should contact consistency.

 

[ab_bentley]

Proven loads aren't "proven" until they've been proven in the rifle your loading them in.
If they've proven accurate in this rifle in the past I'd look for shooter input issues; among them would be rear bag and should contact consistency.

These were/ are proven in this rifle. Here in about an hour we'll know.

Adam

 

[ab_bentley]

These were/ are proven in this rifle. Here in about an hour we'll know.

Adam

Well, the trigger pin was a culprit. Fixing that still didn't bring me back to that usual grouping. Going to pull the trigger and clean it. I still think though I might have roached the throat.

Adam

 

[ab_bentley]

Well apparently my rifle doesn't like RL15 anymore. Switched over to Varget and presto the groups went back to normal

 

[Dusty Stevens]

Rl15 is pretty temp sensitive. You could tweak your load and get it back each day

 

[ab_bentley]

Rl15 is pretty temp sensitive. You could tweak your load and get it back each day

Precisely why I'm using Varget.

Adam

 

[Archer]

Did you happen to see the article on vertical stringing written by the AMU on the front page yesterday. Check or replace your firing pin spring...