I continued today my journey in finding the right seating depth. I was shooting 6-shot groups at 100m. One of the group split into 2 3-shot 0.3moa groups. I was shooting off bipod+SEB rear bag. Unfortunately my labradar is being repaired, so I have no knowledge of velocity, not to mention SDs. Calm weather. Could it be me changing my position behing the gun from shot to shot or is it the load?
Kindly help interpret the target
- Thread starter marchx
- Start date
Clancy
Silver $$ Contributor
What did the other groups look like?
Going off of just this one group, it looks like my targets when I don’t have my shoulder pressure the same for each shot.
It also looks like my targets when I’m not settling the butt into the rear bag the same each time.
It also kinda reminds me of when I shoot prone at a tall target stand at 100 yards.
As @Downeast said, could possibly be the scope. Less likely if the other groups were good and round. Point of impact shifting at all?
Going off of just this one group, it looks like my targets when I don’t have my shoulder pressure the same for each shot.
It also looks like my targets when I’m not settling the butt into the rear bag the same each time.
It also kinda reminds me of when I shoot prone at a tall target stand at 100 yards.
As @Downeast said, could possibly be the scope. Less likely if the other groups were good and round. Point of impact shifting at all?
The bullets look there are tearing the paper checking seating depth an what caliber are you shooting an cases used
Thank you Gentlemen.
1. Stock.
It's oryx chassis, so it's kind of prs setup which I use for F-class. Not the best option, I know. I shoot off F-class bipod and SEB rear bag filled with zircon sand. Only a small portion of the buttstock fits in the ears of my rear bag. So, it happens quite often that under recoil the buttstock is pushed back and I have to put it back between the ears. I consider the buttstock the biggest disadvantage in terms of tracking.
2. Scope/mount. I received this rig from my gunsmith last week and I do not suspect that a monoblock mount hand lapped and torqued according to spec is a source of the problem.
3. position behind the gun. I change my position between shots trying to maintain the same contact with the gun, but let's be frank, it's not always the same.
4. load- 29.8gr N140 .060 off the lands. 105gr hybrids.
1. Stock.
It's oryx chassis, so it's kind of prs setup which I use for F-class. Not the best option, I know. I shoot off F-class bipod and SEB rear bag filled with zircon sand. Only a small portion of the buttstock fits in the ears of my rear bag. So, it happens quite often that under recoil the buttstock is pushed back and I have to put it back between the ears. I consider the buttstock the biggest disadvantage in terms of tracking.
2. Scope/mount. I received this rig from my gunsmith last week and I do not suspect that a monoblock mount hand lapped and torqued according to spec is a source of the problem.
3. position behind the gun. I change my position between shots trying to maintain the same contact with the gun, but let's be frank, it's not always the same.
4. load- 29.8gr N140 .060 off the lands. 105gr hybrids.
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rwj
Gold $$ Contributor
If scope parallax isn’t properly adjusted, this can shift the POI.
correct
groups like this form at 600-8– yards with the different shoulder pressure on the stock or holding the stock tighter for some shots and then looser for others
and we need to know the caliber
I would think your suspect buttstock could be the issue. "Putting your shoulder into the shot", as in excessive shoulder pressure compared to your std hold, is a well-known cause of "11 o'clock" shots amongst fullbore shooters. Maybe the high ones were where the butt got hung up on the bag?? My 2c worth anyway.'
...just read the other replies, seems I'm not alone on that thinking
...just read the other replies, seems I'm not alone on that thinking
IMHO I would suggest a bag rider that fits the rear bag . 
I have that on my other oryx stock. It helps a little with tracking, but it changes also the way the rifle recoils, i.e. the vector of the recoil.
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Today was my second trip to the range with a box full o 95 gr VLDs. I tested them close to the lands instead of extending my seating depth testing beyond .060 off the lands.
Here is my setup- F-class bipod + rear bag. nothing fancy.
The buttstock in the rear bag is a weak spot for sure.
So, first group .010 off the lands. 5-shot group, 100m
second group, jammed in the lands, 5-shot group, 100m
Virgin Lapua brass, necks expanded with 21stcentury expander mandrel, graphite inside the necks, BR4, VV N 140. The biggest variable is keeping the same position behind the gun from shot to shot. manipulating the bipod, loading the gun, adjusting the rear bag position decreases repeatability.
Here is my setup- F-class bipod + rear bag. nothing fancy.
The buttstock in the rear bag is a weak spot for sure.
So, first group .010 off the lands. 5-shot group, 100m
second group, jammed in the lands, 5-shot group, 100m
Virgin Lapua brass, necks expanded with 21stcentury expander mandrel, graphite inside the necks, BR4, VV N 140. The biggest variable is keeping the same position behind the gun from shot to shot. manipulating the bipod, loading the gun, adjusting the rear bag position decreases repeatability.
FIRST ONE-vertically
SECOND ONE- horizontally
Ranger188
Silver $$ Contributor
I had the same issue, I called it ghost groups.
Would have the same size group print a identical group a .1 or two away.
Sent my scope back to the manufacture to check and they found the
reticle was shifting. Fixed the problem.
Might want to mount another scope and see if it still happens.
It was pis#ing me off and this was the last option.
Doesn't happen too often, but it does happen.
This was a big name scope company, not a piece of junk.
Would have the same size group print a identical group a .1 or two away.
Sent my scope back to the manufacture to check and they found the
reticle was shifting. Fixed the problem.
Might want to mount another scope and see if it still happens.
It was pis#ing me off and this was the last option.
Doesn't happen too often, but it does happen.
This was a big name scope company, not a piece of junk.
The rifle is shooting in .3 5-shot groups. The limit for this caliber is a 6mm hole, i.e. 0.24". I have a very simple reloading process, don't sort bullets or cases (not to mention primers). I don't turn necks, just load the powder and shoot. Could it be a brand new march's fault? Yes, it could. It's possible.
Thank you all for your input!
Thank you all for your input!
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