How "important" are certain details when reloading?

[trophyhusband]

Well, I now have some data.

All OAL measurements are using a comparitor so the distance from head to ogive is consistent. The measurements of the group size is in inches measured with calipers and rounded to the nearest .100.

wind was about 5-8 left to right, but I timed my shots for lulls in the wind so I don't think that was much of a factor.


The first pic is an OAL of 3.960
The group was 2.7
Vertical separation was 2.4
Horizontal separation was 1.4

Second pic was an OAL of 3.950
The group was 1.6
Vertical separation was 1.5
Horizontal separation was 1.3

Third pic is an OAL of 3.940
The group was 1.7
Vertical separation was 1.6
Horizontal separation was 1.2

So what does all this tell me? Should I do another round of testing with OAL's of 3.930, 20, and 10? Will there be a trend towards a tighter group or could the grouping be just about anything until I hit that sweet spot?

I used brand new Nosler brass. Should I use 18 more new cases for the next round, or should I use these that are already formed to my gun's chamber? I have a full length resizing die so how do I set up the die to bump back the shoulder .001?

From looking at the pictures, it's clear that my scope is about 1 MOA to the right. Would it be ok to make that adjustment now or should I just leave it alone until I get the load developed?

If I'm going to shoot again in the next couple days, should I clean the rifle?

 

[Sully2]

Thanks for the response. The max case length is 2.850 with a "trim to" length of 2.840. Since quite a few of my cases are shorter than the trim to length, would you suggest trimming the long ones to 2.840 and let the short ones "grow" with use? How much shorter than 2.840 can I use at this stage?

Can you tell me where you found the info on the powder charge? I have a Speer manual that lists 66, 68, and 70 gr of 4831 and a Lyman manual that lists 62-69 gr with 69 being their most accurate.

Latest Nosler manual

 

[trophyhusband]

Latest Nosler manual

Thanks. Since I have about 1200 various Nosler bullets and some Nosler brass it would make sense for me to get the Nosler manual.

 

[benchracer]

To get decisive data, IMO you really need to test seating depth in larger intervals. I believe it noteworthy that the Berger seating depth test specifies .040 increments. I have used that test with many other bullets, including Nosler Partitions, with very good results.

You don't say what distance you were shooting. I recommend doing your initial testing at 100 yards. Once you have your final load figured out, confirm it at longer distances.

When you shoot your test groups, hang one target for each group you plan to shoot. Shoot your targets/loads in round robin fashion to more evenly distribute your error (fire one round from group 1 at target one, one round from group 2 at target 2, and so on).

You fired enough rounds that you should clean your rifle before your next set of tests. Make sure to load some extra rounds for fouling shots before your next test.

While testing, it is not important to be dead on in your scope adjustments. There is no point in adjusting your scope until you settle on a final load. Because your POI is likely to change as you go through load development, trying to adjust your scope for a dead on POA/POI will result in you chasing your tail instead of learning something about your rifle/load combination. Use you fouling shots to get in the ballpark and stop there until you have completed load development. Zero with your final load.

You don't need to use virgin brass each time. You should be able to develop a good load using the same cases that you started with.

 

[Bart B]

I think groups 2 and 3 are virtually the same.

Both the above are close enough to group 1 that the probability of them being smaller to a good confidence level is too close.

In other words, statistically they're all close enough to be equal.

 

[Bart B]

I think groups 2 and 3 are virtually the same.

Both the above are close enough to group 1 that the probability of them being smaller to a good confidence level is too close.

In other words, statistically they're all close enough to be equal.

Regarding the scope's zero, they're a bit to the right which is quite normal when testing a rifle from a bench while holding it against one's shoulder compared to standing, sitting or prone field positions' zeros. I wouldn't change anything yet.

 

[MR.SWIFT]

at this point i would reshoot the loads with the smallest group at the same distance. then shoot the load that displays similar grouping at the max distance you intend to shoot. finally work with the loads that displays the best group at both distances.

 

[trophyhusband]

To get decisive data, IMO you really need to test seating depth in larger intervals. I believe it noteworthy that the Berger seating depth test specifies .040 increments. I have used that test with many other bullets, including Nosler Partitions, with very good results.

You don't say what distance you were shooting. I recommend doing your initial testing at 100 yards. Once you have your final load figured out, confirm it at longer distances.

When you shoot your test groups, hang one target for each group you plan to shoot. Shoot your targets/loads in round robin fashion to more evenly distribute your error (fire one round from group 1 at target one, one round from group 2 at target 2, and so on).

You fired enough rounds that you should clean your rifle before your next set of tests. Make sure to load some extra rounds for fouling shots before your next test.

While testing, it is not important to be dead on in your scope adjustments. There is no point in adjusting your scope until you settle on a final load. Because your POI is likely to change as you go through load development, trying to adjust your scope for a dead on POA/POI will result in you chasing your tail instead of learning something about your rifle/load combination. Use you fouling shots to get in the ballpark and stop there until you have completed load development. Zero with your final load.

You don't need to use virgin brass each time. You should be able to develop a good load using the same cases that you started with.

Thanks for mentioning the Berger test, I had not read that before. Also the round robin method clears something up for me. I had been wondering how much the barrel heating up and getting dirty effected each group. Doing it round robin style evens out those factors.

BTW, I am shooting at 100 yards. I should have mentioned that but I forgot.

Next i'll be looking up how to set up my press so that I don't mess up the cases that I've already fired in my gun, but if anyone wants to jump in here and give me a quick tutorial or can give me a link to a good tutorial it would be greatly appreciated.

 

[Bart B]

I had been wondering how much the barrel heating up and getting dirty effected each group.

If your point of bullet imact moves as the barrel heats up, it's either fit improperly to the receiver or made with poor metal. Good barrels properly fit don't walk shot impact as they heat up.

If the barrel doesn't shoot accurate from the start of group shooting and needs a few to several shots through it to shoot accurate, it's got a rough enough finish in the bore that jacket material has to be wiped off several bullets to fill up the rough spots until no more bullet jacket material's rubbed off subsequently shot bullets. If this is the case, then don't clean it squeaky clean after each shooting session. Leave some copper in the bore so it'll shoot to point of aim next time out.

 

[roninflag]

my experience- the barrel, scope and trigger are way more important than loading details. pour some appropriate powder in case scrape it off with a butter knife crunch a bullet down if you have a good barrel . if you are shooting through a 17$ factory barrel it can not compare to a 400$ barrel. think of it this way- similarly ...cars with a $1700 engine pulls up next to one with a $40,000 engine ........ that said if you want to know the capability of your 721 first make sure the trigger is adjusted. put on a higher power scope . load some 175 grain match bullets 010 off . besides the powder you are using i would try h4350.

 

[roninflag]

if you are using nosler brass it is already weight sorted and match prepped. the 721 is a fairly light rifle and the h&h generates quite a bit of recoil. the last group is getting there. the vertical generally is the rifle/shooter, the horizontal -wind. sometimes/usually going up in powder charge (.5 grain at a time) you can reduce the vertical .

 

[roninflag]

i resize only enough that i do not bump back the shoulder. there should be a black ring on the case neck showing how much more you have to go. on a 300 h&H i would have it come around 90%-95 % down the case neck.

 

[Bart B]

i resize only enough that i do not bump back the shoulder. there should be a black ring on the case neck showing how much more you have to go. on a 300 h&H i would have it come around 90%-95 % down the case neck.

I know this is a popular way to resize fired cases, but when I talked with folks who shot the .300 H&H in long range matches, the ones winning and setting records had the following comments about sizing fired cases.

Any fired case sizing tool and technique that doesn't set the fired case shoulder back a bit typically ends up making the case headpace (head to shoulder distance) at or a bit longer than chamber bolt face to shoulder distance. This ends up causing the bolt to bind as it's closed on a chambered round. If the bolt face isn't squared up with the chamber axis, binding is more common and accuracy suffers. Problems are caused by the bolt head long locking up in the same place for each shot and that changes the amount and direction of the barreled action's whip while the bullets are going down the barrel; they all don't leave at the same angle relative to the line of sight when fired.

The fired case shoulder needs to be set back a thousandth or two so the bolt won't bind closing on a loaded round. This lets the bolt close to the same place for every shot. The barreled action whips more consistantly and accuracy is better. Note the benchresters have to resize their cases that bind up when the bolt's closed, otherwise their accuracy degrades a bit.

Those who've measured case neck runout on resized cases have seen straighter neck better centered on bottleneck cases when full length sizing dies are used sizing all of the neck and setting the shoulder back a bit. This method holds the case body and shoulder in place while the entire case neck's sized down. Sizing the case neck down just enough without expander balls using dies with correct neck diameters typically do a better job at this than any neck only sizing die or partial neck sizing with a full length die.

It was interesting to hear these folks state tha new .300 H&H Mag cases shot as accurate as properly resized fired ones as long as the bullet was seated out long enough to gently push into the rifling when chamberd.

Food for thought even if you think it all a bunch of baloney. I've shot belted magnums enough to see the realities of this.

 

[roninflag]

Bart- That all sounds resonable to me. the reason i don't set back the shoulder is case stretching/separation. Having shot in competition out to 1000 yards i can tell you as much as i like remingtons and sakos; there were no sporter weight factory rifles where i shot in the SW region LR/HP championships. for my hunting rifles I resize enough to get reliable feeding/chambering.