First round of load development now what

G

GSoD

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Hey,

Well, I actually pulled it off. Finally took my first batch of reloads to the range. All fit in the magazine, all fed, all fired, none blew up in my face. Had a couple of fliers but I expected that as I was having some consistency troubles with my bullet runout (seating die problem I suspect)

Couple of questions for the pros :

a) Is my math correct?

I measured my best group from outside edge to outside edge of the two furthest holes. They measured 1.35" apart. I was firing at 200 yards, so I figure I divide by 2 to get an approximate 100 yard reading. This gives me a reading of .678 inches. I then subtracted the caliber of the bullet to give me the centre to centre reading. .678 - .308 equals .370.

Did I do this right?

b) Now what?

My best group (.370 if I measured correctly) mentioned above was acheived with 44.4 grains. At 44.7 grains the group increased to .518" and at 44.1 the group increased to .567" What is the next step? Do I put together batches in .1 grain increments from 44.2-44.6? Should I consider .370" to be pretty much as good as its going to get with an out of the box non-custom rifle, slap a bunch together at 44.4g, test for repeatability and chronograph for suitability for long range?

c) Too much?

Lets say I stay in the 44.4g neighbourhood. Is this an excessive load in regards to will it shorten gun life or invite early catastrophic failure or is this a happy place to be?

c) No pressure signs?

I worked up from 42g of Varget to 45g of Varget and inspected each case after firing. But I didn't notice any obvious pressure signs. No cracked necks, no flattened or pushed out primers. No visible signs of case seperation. Is this normal or is this confirmation I don't know what I'm looking for?

SPECS:
Gun - Remington 700P with Jewell trigger set to 2lbs
Caliber - .308
Barrel length - 26"
Bullet - 175g Sierra HPBT
Powder - Varget
Primer - CCI
Brass - Once fired federal, full length re-sized, trimmed once to 2.015
OAL - 2.810
Load development range - 200yards
Load increments - 42g-45g in .3grains
Best load - 44.4g with .370" group
Goals - 99% Recreational target shooting from 300-1000 yards and !5 Moose hunting within 300 yards.

PS - Thanks to everyone here who has helped me directly by answering my questions or indirectly by posting their info. I can only assume this is why my first time out was such a riot success.
 
1) I do not believe this is how you calculate MOA at 100yds. (See forums).
2) If you are happy with the group take it out farther to 300.See
what the results are with that load.
3) Check the books for max load for that bullet weight and powder. Do not exceed. Safety First.
4) Flattened primers would be a telltale sign of too much pressure. Again check the books.
Other members may be able to add more. Otherwise it seems like a good load for an out of the box rifle.
 
1.35 @ 200 is just over 1/2 moa. subtracting the bullet diameter puts you at just around +/- 1/2 moa.

You can assume that at 100 you MAY shoot 1/2 moa. or you may shoot in the .3's or you may shoot the next 10 groups at 100 into the 1's and/or 1.5's as well.

I have a feeling your math is wrong by trying to 1/2 the group size for 100 but it doesn't work that way as 1/2 MOA is 1/2 MOA no matter how you slice it.

I know that a 1/4 moa group that I shoot at 100m is most likely NOT going to be 1/4 moa at 200, 300, 500 etc...as weather, temperature, humidity, time of day, amount of caffeine intake and many other variables can affect your grouping. The longer the bullet is in the air the longer the elements have time to wreak havoc on it.

Don't get me wrong, a 1.35" group at 200 is a great group, but.....load up another 20 and shoot 4 more 5 shot strings then average out the group measurements. That should give you a much better idea whether it will perform for you.
 
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Your load seems in the ballpark, though I agree with the others that your math is off. Take the edge-to-edge measurement, then subtract the bullet diameter. That gives you your group. Then you can divide it by two if you are shooting at 200 metres. The group you described is hovering somewhere in the .5s.

Was it a 5-shot group, by the way? On a serious rifle like a 700P, I'd go with 5-shot groups. 3-shot groups are for hunting rifles.

Speaking of hunting, you mention that you'd like to hunt moose with this rifle. That would be great, but you should NOT use the Sierra matchking. Personally, if I were going to hunt moose with a .308, I'd go with either a 150 or 168-grain Barnes TSX, though there are lots of other bullets that would work, too, like the plain-old Nosler Partition or the newer Accubond, or even the Sierra Pro-Hunter. However, the Sierra Matchkings are NOT designed for big game hunting and they can give erratic performance when they hit living flesh. Some will zip through an animal like a pencil, leaving a narrow wound channel; others will blow apart like a varmint bullet, leaving only a flesh wound; and others from the same batch will work perfectly, holding together and penetrating deeply, like a Nosler Partition. They have unpredictable terminal performance, so they should only be used for punching paper -- where they excel.
 
Thanks - your math sounds better than my math for determining group size.

It is 5 shot groups.

No worries - I'm using the rifle for hunting not the bullet. I'll work up something like a 180g Nosler Ballistic tip for that. I got me two last fall.
 
This quote from GSoD,

c) No pressure signs?

I worked up from 42g of Varget to 45g of Varget and inspected each case after firing. But I didn't notice any obvious pressure signs. No cracked necks, no flattened or pushed out primers. No visible signs of case seperation. Is this normal or is this confirmation I don't know what I'm looking for?


The two items you mention, cracked necks and case seperation, are not caused by excessive pressure, thus are no indication of pressure.
Primers are a fair way to judge pressure, but primers being pushed out is also, not a sign of excess pressure. All primers are not the same and some may flatten worse than others with a given pressure. If the primer craters around the firining pin indentation it is usually a sign of too high pressure.
Pay attention to how the bolt opens. It should open as easy with the fired case as it does with an unfired case. If the bolt handle is hard to lift, then when the case comes out there is shiny marks on the face of the fired case, this means the case was stuck in the chamber and the pressure of that round was too high.
A sure sign of pressure that is much too high is if the primer socket enlarges. When reloading you should always take note of how the new primer seats. If the primer goes in easy, or easier than it did last time, the socket is enlarged by a load which was far too heavy. Throw away cases that have enlarged primer pockets reduce your load.
 
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A. It's not, but you still have a sub-MOA rifle and load. Groups are measured centre to centre on the two holes farthest apart. Outside to outside and subtracting a diameter will do though.
B. Sight in. You could go back to 44 grains and work up by 1 grain to 44.4, but it'd likely only give you a slightly smaller group.
C. 45.0(compressed) of Varget is max. You're fine. It's not unusual for the best accuracy to come close to max either.
When you get that far, work up a load using 165 grain Gamekings with the same powder, etc. Pity they don't make a 175 grain Gameking. Your rifle likes that bullet weight. Test the loads at 100 yards and when you find the best group with the 165's, sight in 4" high at 100 and you'll be on target out to 300. You don't need match quality groups for hunting though. Two inches or so will do.
 
My previous remarks on pressure were misleading on one point. I said the bolt should open as easy with the fired case, as with an unfired. Most bolts #### on the lift of the bolt. Therefore, lifting the bolt handle compresses the spring and takes some effort. With the bolt closed, but not fired, the bolt handle lifts very easy, because it does not have to compress the spring.
What I should have said is the bolt should remove the empty with no more effort, or only slightly more effort, in lifting the handle, than is required to lift the handle on an empty chamber, with the firing pin released.
 
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