Working on reloading for my Mauser 98 in 338-06. I have Remington 30-06 cases that I necked up to .338, I've formed them with starting charge loads and reloaded some with various charge weights. I've handloaded before and notice some change of POI with charge weights, but this rifle has literally climbed 1 foot at 100yds from min to max. I find that excessive, and I believe there to be a bedding problem with the rifle. It's a Hogue stock with the aluminum bedding system and an aftermarket trigger guard. I ran into some issues with the bolts binding so I opened up the action bolt holes in the stock so the bolts go in without bind. It helped accuracy some. Still could use to be better. I have started another thread in gunsmithing about trying to glass bed this rifle and it is a related thread.
POI shift with powder charge change
- Thread starter cgarb
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I have had rifles do the same thing, most of the time I shot the groups too fast and the barrel was hot. But the bullet is gaining speed so poi will change
I believe your POI shift that you are seeing the physical manifestation of your barrel's harmonics on the target. Not saying that you may not indeed have a bedding related issue though. 12" is a lot of shift at 100 yards. I've had a couple rifles that had 4" shifts, but ymmv.
Harmonics are most directly related to barrel time (velocity) more powder usually means more velocity and less barrel time. How much a barrel resonates is related to its rigidity which is related to length, diameter, composition ect.
Harmonics are most directly related to barrel time (velocity) more powder usually means more velocity and less barrel time. How much a barrel resonates is related to its rigidity which is related to length, diameter, composition ect.
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Yes and no, the starting loads at 55grs were the most accurate so far, 57grs opened up some, 58 and 59 it tightened back up, but each grain increase the POI shifted close to 3" higher. It's not accurate enough to be acceptable for me yet. There is still more work to be done. The barrel is free floated and with Hogue stocks I heard that can be problematic, I plan to, after this year's deer season to experiment with forend pressure some and see if that helps it out some more. If I can get it to 1MOA or under then I can live with that. 55grs was close, I would say 59gr load was 1.5MOA.
It could be a mechanical issue such as bedding but it could be the load. The OCW load development method will help find a load that does not do this. This is assuming the rifle is capable. If not shooting long range it's not near as important. In long range hunting having a stable load is just as important if not more so than having an accurate load.
DUSTY NOGGIN
Well-Known Member
what weight bullet
I'd also say focus on the optimal charge weight over the accuracy workup method of load developement... with a slower moving heavy bullet .. keeping it moving the same speed will be more important the father out you go
I'd also say focus on the optimal charge weight over the accuracy workup method of load developement... with a slower moving heavy bullet .. keeping it moving the same speed will be more important the father out you go
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DUSTY NOGGIN
Well-Known Member
i messed with numbers every way i could think if to get a 12" climb , and with the update 200 grn bullet moving faster , made it even tighter . gotta be gun related
lancetkenyon
Well-Known Member
Sporter weight barrel? Sounds like barrel harmonics like others have stated.
Shoot a ladder test, at 400 yards, on a tall target, over a chrono. Find your accuracy node. Then work in that range.
Maybe try Varget, H4895, IMR4064?
Shoot a ladder test, at 400 yards, on a tall target, over a chrono. Find your accuracy node. Then work in that range.
Maybe try Varget, H4895, IMR4064?
lancetkenyon
Well-Known Member
It will tell you where an accuracy node is during a ladder test. You are not shooting for groups. You are shooting to find a node for your powder charge, then work in that node for best accuracy results. Go hang a 4'x8' piece of plywood with some butcher paper taped to it. If you can't keep them on that @ 400, time to ditch the gun. Not much you can do with it other than beat a deer to death with it.
At 400 yards, if the load is worth even exploring, you will see a spot in your charge weight increase where the bullets stop rising. A flat spot if you will. You absolutely can not repeatedly and reliably see this at 100 yards. The random scatter alone will give false data and it is exasperated by a less accurate rifle. At 400 yards(I prefer farther) the change in velocity, or lack there of, will show you where the node is. Then you can tweak seating depth to get the most accuracy from the load.
