I am working up a load for my Marlin 336 30-30 using Lyman 173 gr cast.
I am testing loads with both Reloader 7 and SR4759. Getting
pretty good results at around 14.5 gr of SR4759 and 20.0 gr Reloader 7. Which should put me at 1500-1600 fps.
Problem is that there seems to be 2 distinct points of impact. A typical 3 shot
group will have 2 touching and 1 shot down and right 1.0 - 1.5 inches.
Sometimes the first 2 touch. Sometimes 1 and 3 will touch.
I am cooling the barrel for 5 minutes between shots and it never gets very
warm.
Shooting 50 yards.
I am shooting off of sand bags under the receiver.
Using a Williams peep with the smallest hole (I don't remember the size, but its the smallest I could get from Midway)
Trigger is very good. I installed a Wild West Happy Trigger 2 years ago.
Bullets are sized to .311. Barrel slugged .309. Bullets sized .312 can be hard to chamber, so I think they are a good fit.
So, what do you think. Is it barrel heating (do I give more than 5 minutes?).
Is it technique?
Is it normal?
Bob A
Help me figure this out
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Re: Help me figure this out
Maybe it is as simple as the gun shifting in the sandbag. Try picking up the whole rifle and setting it back down between shots. You could be having a slight shift at the second or third shot.
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"Worldwide Hunting Adventures"
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Re: Help me figure this out
Another thought - the powder is shifting in the cases due to recoil. Point the gun upward and tap the receiver for each round and see if it makes a difference.
Professional Hunter
http://www.TARSPORTING.com
"Worldwide Hunting Adventures"
Professional Hunters Assoc of South Africa
SCI - Life Member
NRA - Life Member
NAHC - Trophy Life Member
DWWC - Member
http://www.TARSPORTING.com
"Worldwide Hunting Adventures"
Professional Hunters Assoc of South Africa
SCI - Life Member
NRA - Life Member
NAHC - Trophy Life Member
DWWC - Member
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Re: Help me figure this out
Shoot those loads over a Chronograph ! Could be as simple as a change of primer or maybe 1/2 gr powder either way will settle her down. Do your gas checks fit good and tight? Could be loosing one once in a while?
Re: Help me figure this out
Thanks for the inputs.
I am loading one at a time. Picking up the rifle and loading the cartridge with the rifle pointing straight up. Then settled back down onto the sandbag.
Gas checks seem to be tight. I don't know if some are falling off. How would I tell?
I am using CCI LR primers and Win cases. Is there a better primer choice for this kind of load?
I think the only other options available locally are CCI Magnum, BR or Winchester LR.
I haven't shot them over the chrono but that's a good idea. Maybe I will set it up next week.
I try to take a mental health break on Wed mornings and sneak out to the public range. They open at 10:00 AM on Wednesday and its usually pretty empty till noon.
I can (and do)shoot at home on the weekends, but the range here is pretty nice and its a lot better than 2 hours in the office.
Bob A
I am loading one at a time. Picking up the rifle and loading the cartridge with the rifle pointing straight up. Then settled back down onto the sandbag.
Gas checks seem to be tight. I don't know if some are falling off. How would I tell?
I am using CCI LR primers and Win cases. Is there a better primer choice for this kind of load?
I think the only other options available locally are CCI Magnum, BR or Winchester LR.
I haven't shot them over the chrono but that's a good idea. Maybe I will set it up next week.
I try to take a mental health break on Wed mornings and sneak out to the public range. They open at 10:00 AM on Wednesday and its usually pretty empty till noon.
I can (and do)shoot at home on the weekends, but the range here is pretty nice and its a lot better than 2 hours in the office.
Bob A