300WM confusion

J

jpbaker

CGN Regular
Rating - 100%
30   0   0
Location
Grand Sault
Ok folks, i went to the range a couple days ago to develop a new hunting round for my 300wm.

I found a load that appeared promising which included 185gr Bergers with 73.5gr of H4831. This printed a .6ish group that included 1 flier.

I went back out yesterday to chrony the new load and im confused by the results.

Here is the first three out on my rifle. Note the rifle was not cleaned prior, so it was already fouled.




Frusterated, i switched to another target about 8 inches above this one and here is the result.



Im confused, I checked the scope, action screws, etc. everything seems torqued down to spec.

What are you guys thinking?

conclusion on post #20

TKS
JPB
 
Last edited:
I am thinking there isn't enough data to make a conclusion... and the .6ish wasn't a .6ish. (count the flyer)
 
lower target you were resting barrel on something cuasing upward psi. on barrel.when shooting the higher target you lifted up a bit ? sounds goofy but barrel psi will deffinatly mess with your grouping.
 
Neat shooting, does it happen all the time? On one hand you shouldn't complain as either group would net you any big game you aimed at. On the other hand, check your variables - as you did with some - but also check yourself for consistent hold, placement on the rest, how you hold the rifle on the rest, wind affect, light conditions, down range conditions like a different cross wind speed, feet placement at the bench, breathing control, eye distance from scope, scope mount condition, and even elbow placement at the bench. From the look of the group, I will stick my neck out and say it is the result of different hand and holding placement on the rest. The best advice is to shoot more and look for a pattern. Feel free to pm me after you have shot more.
 
guntech said:
I am thinking there isn't enough data to make a conclusion... and the .6ish wasn't a .6ish. (count the flyer)
Click to expand...

I may disagree. Occasionally I will shoot a three shot group and "I call the shot" that I pulled one right or left (a flyer) so I shoot a fourth shot and measure the best three. as a group. That is if you are after the best the rifle will do and not the best the shooter will do on the day.

I read somewhere that to really prove the best group of a rifle, one should shoot 7 shots into the target.


To the OP, I find that some times I just wiggle one out of the best group (a flyer) perhaps you just wiggled two out of your first group and then were able to bare down and shoot better after that. Would one shot of the first group fit in nicely to the second group?
 
broadhead67 said:
lower target you were resting barrel on something cuasing upward psi. on barrel.when shooting the higher target you lifted up a bit ? sounds goofy but barrel psi will deffinatly mess with your grouping.
Click to expand...


What you are saying is that the barrel was contacting the stock? And changing harmonics? The rifle is a glass bedded A-Bolt II. While the foreend is not particularly stiff, there is a decent amount of clearance. I will check that next time im out.

TKS
JPB
 
I think that you sat down to shoot your first group and weren't "warmed up" yet. Or you were still recovering form coffee jitters or whatever. A third group would have explained quite a bit.
 
Duffy said:
To the OP, I find that some times I just wiggle one out of the best group (a flyer) perhaps you just wiggled two out of your first group and then were able to bare down and shoot better after that. Would one shot of the first group fit in nicely to the second group?
Click to expand...


Not really, the top pic or the first target, is upside down, so the first shot was almost 2" low second up an inch, third up another inch. Then it started to group on the next target.

TKS
JPB
 
Gatehouse said:
I think that you sat down to shoot your first group and weren't "warmed up" yet. Or you were still recovering form coffee jitters or whatever. A third group would have explained quite a bit.
Click to expand...



Lol I had just finished working on some .308 loads, that where shooting well. (Scenars are spectacular!) but maybe i needed the coffee :)
 
It could be one of a number of things. How clean was your gun with the tight group? How dirty was your gun with the large group? IMO and what I have practiced in load development is prove the integrity of a load by shooting several three shot groupings.(dirty and clean barrel) If you only shot one group with your load it is not really testing its integrity as you presumed. Flyers or fouling shots does not test the honesty of the load and firearm, dirty or clean it should have the same POI. What brass are you using? Remington and Winchester brass is most inconsistent in weight when measured. When case wall thickness are inconsistent it will result in pressure fluctuations, therefore it would be prudent to weigh your brass. Did you make any changes from one load to the other?
 
track said:
It could be one of a number of things. How clean was your gun with the tight group? How dirty was your gun with the large group? IMO and what I have practiced in load development is prove the integrity of a load by shooting several three shot groupings.(dirty and clean barrel) If you only shot one group with your load it is not really testing its integrity as you presumed. Flyers or fouling shots does not test the honesty of the load and firearm, dirty or clean it should have the same POI. What brass are you using? Remington and Winchester brass is most inconsistent in weight when measured. When case wall thickness are inconsistent it will result in pressure fluctuations, therefore it would be prudent to weigh your brass. Did you make any changes from one load to the other?
Click to expand...

The rifle had aprox 12rds since last cleaning. Im using winchester brass. They were all loaded at the same time, so there was no difference between the loads. Brass weight is a good point.

I will hit the range again soon, and see what happens. Will shoot 4-5 groups

TKS
JPB
 
I've had a few barrels that only really started shooting after they warmed up a bit. More that had to be cold. A very few needed to be squeaky clean and many more that filthy is what flew. In any case it takes a lot of shooting for the patterns to become apparent, and then only if you are looking for it.


In your case the first and second groups aren't even close to the same zero. That may be your barrel talking to you; now you have to see if it says the same thing every day.

In a general sort of way, .300s like the crap loaded out of them, Bergers tend to like being jammed. I've had some luck putting upward pressure on finicky free floated barrels, and the opposite on pressure bedded barrels.I 've had more consistent luck unscrewing barrels that pissed me off. Sometimes its cheaper in the long run.
 
I agree with Guntech and Dogleg.........not enough data to draw a definitive conclusion......how long between first group and second group? The barrel may have stresses that only stabilize after the barrel is warm....quite common......but not enough data. After 1000s of rounds with many 300 WMs I found the same as Dogleg, the groups keep getting smaller as the pressure goes up and best accuracy was attained with some pretty steamy loads.

I worked with a guy when I was in my late teens that shot groups a very different way (this isn't exactly on topic but interesting none the less) Everyday he would bring his rifle, a Rem 700 7Mag IIRC, to work for 10 days straight. On his way home he would stop at a range set up his target and fire 1 shot, take down his target and go home. At the end of 10 days he showed me his target and his 10 shots were all in approx 1 1/4". He stated that this was the correct way to check accuracy for a hunting rifle, and I could see his point. He said none of that other crap mattered as long as the first shot out of a cold, fouled barrel went the same place every time.
 
Last edited:
c-fbmi said:
After 1000s of rounds with many 300 WMs I found the same as Dogleg, the groups keep getting smaller as the pressure goes up and best accuracy was attained with some pretty steamy loads.
Click to expand...

Got ya, the 73.5 H4831 is not "steamy" at all. Max load is running around 76gr. So overall its a pretty mild load. I will try to work it up a bit more next time im out. However, these bullets are hard to find.

TKS
JPB
 
Just something I found that works for me.
I usually take a rimfire with me and pound some rounds off
before shooting the bigger ones.
Set the mind straight and get the harmonics of me straight.
Then tend the task of making tighter big hole groups.
Another sure fire way to tighten groups is take a known
tight arse group shooter with you.
I will bet your groups will tighten up just to save sum facia rosa.
 
My M1 Garand does this, once the first 8 rounds are through it tightens up groups, clean barrel, fouled barrel seemed to make no difference. That's a semi though, a lot of peculiar variables, your situation I'm just not sure. I'd be looking at any loaded rounds you have left from the batch for neck tension, and double check OAL is all the same, as a starter.

This all said, it's usually the wizard not the wand, I suffer from it too. The M1 Garand I mentioned has a Krieger barrel and can produce MOA 3 shot (4 shot actually) groups. I put four into an inch yesterday, then one flier, and the next group was 10 rounds into 4" despite cooling time. Voodoo.
 
Ok i know i am resurrecting an old thread, but for a little update...

The problem was inconsistent neck tension from improperly annealed brass.

I decided to reload some virgin brass, and problem solved.

TKS for all the advise peeps!

Jordan
 
You must log in or register to reply here.
Back
Top Bottom