Ass-u-me!!

.308--win

.308--win

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OK, we all know what assuming does!:) Went to the range last weekend to work some 150grn loads for my 7-08, started @ min worked up to max, will almost. Min load was 45grn of H4350, Max 48.5c of H4350. Only went to 47grn. Anyways, as I shot each(3 round) set, cooling between, this is what I found(excluding 45 & 45.5grn) Groups seemed to get tighter between 46 & 46.5grn:
46grn 3 shot group:
IMG_0622.jpg


46.5grn:
IMG_0623.jpg


47grn:
IMG_0625-1.jpg


So with the given results, 2 questions:
1- Should I "Assume" best results are between 46 & 46.5?
2- If so, how much will a .2grn powder charge affect the load at this point?

Any and all in put will be greatly appreciated!

Thanks,
Perry
 
I would try the 46.5 and play with seating depth. That looks like it wants to be a load assuming the two almost touching were the first two.

The other way to find the sweet spot os with a chronograph. You will often find that a load of powder will tighten the spreads in velocity. When i find that I then adjust seating depth by .005 increments to see if a great load comes out of it.
 
If you shooting 3 rounds per load I'd shoot the same ones again and add in 47.5 and 48 if the pressure is ok. I always like to see the group repeated before I focus in on fine tuning but also try multiple distances off the lands as well with new bullets.
 
If the round is to be fed from a magazine, very often you don't have much latitude to mess with the seating depth. What is the rifle for? If it's a big game rifle, then 1.5 MOA is certainly going to get the job done, and you'd be hard pressed to shoot more accurately in the field. You don't shoot groups at game anyway. If it was me, I'd go with the 46.5 gr load and shoot it at ranges out to 300 to confirm the drop, to see if the 1.5 MOA holds up at long range, and see how the bullet behaves in the wind. If it doesn't meet my expectations I would change to another bullet.

You might see some minor improvement by splitting to a quarter grain, but you are getting close to where the limitations of the powder scale, and weight variations of the bullet and cartridge case over shadow any potential benefit. In any case, dropping or adding a quarter grain will not take a 1.5 MOA load and make it a .75 MOA load. I wouldn't bother, but if you want to experiment go ahead. Anything we try adds to our learning curve.

If the load is for a hunting rifle, power trumps accuracy (within limits), and reliability trumps both. If you stumble onto a load that plants the first cold barrel shot precisely to the same point time after time, that's the load I want, even if it's a 3 MOA load.
 
Before you do anything make sure the barrel is free floating. try working up the podwer more. when working with seating depth seat to the lands. some barrels like a jump but seating a bullet to the lands should be the most accurate.
try some R-15 or some H414.
 
Thanks guys! I will be playing with this load alittle more for sure! This is a hunting load, so if it doesn't get any better than 1.25" I'm sure it will still work pretty darn good!:redface: I just get alittle annal with this stuff! Again thanks for all the tips and hints, They are appeciated!!

PS: Hey crout, barrel is free floated.

Perry
 
Take something like thin cardboard/heavy paper/ piece of leather, and push it under the barrel at the front of the stock. Use enough thickness to put some tension on the barrel and try that for a group.
Like someone said, three shots is not enough. Try a five shot group and show us what the rifle did.
 
PS: Hey crout, barrel is free floated.


Take something like thin cardboard/heavy paper/ piece of leather, and push it under the barrel at the front of the stock. Use enough thickness to put some tension on the barrel and try that for a group.
Like someone said, three shots is not enough. Try a five shot group and show us what the rifle did.
If it is the Salmon Arm range you are coming to, let me know and I will try to meet you there.
 
H4831 said:
PS: Hey crout, barrel is free floated.


Take something like thin cardboard/heavy paper/ piece of leather, and push it under the barrel at the front of the stock. Use enough thickness to put some tension on the barrel and try that for a group.
Like someone said, three shots is not enough. Try a five shot group and show us what the rifle did.
If it is the Salmon Arm range you are coming to, let me know and I will try to meet you there.
Click to expand...

The rifle is a Rem 700 sps, the barrel is free floated, except for the pressure point at the front of the forestock,Guess thats not really "FREE FLOATED". I know the gun is able to make tight groups, 2 weeks ago I hit the range with my dad and zeroed some 140 loads for a bear hunt, out of a 4 shoot group we could cover 3 with a quarter! and ~3" group at 200yrds. I'll be hiting the range again on sunday with some loads with different seating and see what happens! H4831, would be happy to meet you one day;), I fling my lead at the Clearwater range, next time I'm heading through Salmon Arm, coffees on me!!!:D

Perry
 
A 1.25" group isn't exactly terrible.
"...could cover 3 with a quarter..." Where was the 4th bullet? It sounds like your rifle likes the 140's better though. They'll do nicely. It's not unusual for a rifle to prefer one bullet weight over another either.
3" at 200 is 1.5 MOA. Sight in(I'd be thinking 3" high at 100. That'll put you in the kill zone on Yogi out to about 250) and go practice with that load, off hand, until you can hit a 9" pie plate every time at 100.
 
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