F T/R Competition Load Development Stage 2

[b_4]

I have completed my ladder testing at 525 yards and my load of choice is:

Winchester Brass
CCI BR2 primers
45.8 grains of Varget
Berger 155.5 Fullbore
COAL 2.81 in.

Average MV 2900 fps for the three shots

This node grouped

I have since performed the split case test and measured COAL to find the rifling for this bullet and case in my Savage 12 F/TR and after testing 5 times with three bullets each the COAL just touching the rifling averaged 2.937 in.

So now I need to increase my COAL from 2.81 to just off of 2.937 to see if I can improve upon the ladder results for this load. Any tips?

Edit: I am considering the following load out:

Sighters.....COAL = 2.81
Group 1......COAL = 2.84
Group 2......COAL = 2.87
Group 3......COAL = 2.90
Group 4......COAL = 2.917 or 0.02 in off of the rifling

Working my way up in COAL using 4 shot groups.

 

[memilanuk]

Re: Load Development Stage 2

Since you are going off COAL, would it be safe to assume you don't have any tools capable of measuring off the bullet ogive instead of the OAL?

If thats the case, I'd strongly suggest you get one. The comparator inserts from Sinclair Int'l would be my recommendation. OAL varies enough from one bullet to the next even in the same box that I would urge you to not try going anywhere near the lands based off that measurement. Again, I can't emphasize enough the need for the right tool for the job - something that measures the seating depth off the ogive of the bullet.

Having put a *lot* of B155.5BTs down range over the past few years, I'd say skip the trouble of trying so many different seating depths. Some people find they work pretty well @ 15-20 thou off the lands; others (myself included) get outstanding results with them 45-50 thou off the lands. Seating the bullets out that much further means you'll probably want to adjust your powder charge up a bit as well. 45.8gn Varget / 2900fps is definitely on the low end of things

 

[scaxeman]

Re: Load Development Stage 2

Monte is absolutely correct, a comparator tool of some sort to measure seating depth off the ogive of the bullet is an absolute must.

In addition, if you want to experiment with changing seating depth, the 155.5 is extremely forgiving. I'd therefore test different seating depths in increments of .010", rather than .003"... more efficient. In the testing I've done with them, I've found that they like being jumped ~.025-.030". Just to see what would happen though, I mixed in a round that had been seated to jump ~.060". This was in a chronographed test that was also a group test. The round that jumped the extra .035" was exactly in the middle of the group on target, it was also in the middle of the range for velocity. Basically, that bullet is remarkably forgiving for differences in seating depth.

<span style="color: #990000">Whoops! Disregard the .003" comment - basic math evidently difficult this eve!</span>

As Monte said, you have plenty of room to increase the velocity of your rounds with that particular rifle. If you will be shooting 600 yards and under, your current one will do just fine. If you plan on taking it to 1000 yards, you should be looking for a muzzle velocity much closer to 3000 fps.

Hope this helps,

Darrell

 

[Greg Langelius *]

Re: Load Development Stage 2

When Monte talks, I listen.

When I'm done listening, I try to gleane out the salient points. I try to find some compatibility with my own experiences. In some instances, such compatibility seems possible.

I too believe that a definite jump is a good thing, and have no argument with making it a longer one. My question is whether the use of a comparator is such a crucial issue with those longer jumps, and whether working according to OAL is a mistake. Honestly, I simply don't know.

I recognize that the accepted way of managing neck tesion is to establish a .002"-ish neck diameter smaller than bullet diameter relationship and run with it. I think that's overly trusting. Neck hardening turns that approach into a sliding scale of neck tension as brass gets worked over and over.

I think there's a better way and I try to use it. It involves variable partial length neck resizing and is covered in detail elsewhere; but the salient point is that the amount of neck length being resized is set for each reloading according to a neck tension/bullet twist test, and therefore has a real basis in actual performance.

It also comes as no great surprise to me that the load data worked out at 45.8gr of Varget and is considered as being on the light side. Common wisdom here has usually been that 46.0 of Varget is the 150/155 load, 45.5 for 168's, and 45.0 for 175's; works for a lot of folks here.

Darrel's observation about some specs being forgiving simply reinforces my trust in some more common wisdom; when you find an accuracy node, it's usually because the barrel harmonics open up a window of forgiveness. It's this window that makes the accuracy possible, because despite our best efforts at consistent handloading, there are always significant factors in ammo makeup that are simply beyond our control.

My goal is to find out where the leeway lives and use it to simplify the handloading process. Some of the things we do are simply wasted effort when such leeways exist. The key is, we just gotta find 'em. If Federal can make such genuinely good ammo as Gold Medal on commercial production lines, those leeways have got to be real.

Greg

 

[scaxeman]

Re: Load Development Stage 2

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body"> My question is whether the use of a comparator is such a crucial issue with those longer jumps, and whether working according to OAL is a mistake.
Greg </div></div>

I have found that even the best competition bullet's base to meplat measurements can vary by as much as .015", therefore your 'perfectly' loaded rounds can vary by around this much. The base to ogive measurements only vary by .001 or .002"; generally a much more accurate way to measure your bullets, and by extension, your loaded rounds. It takes no extra time at all to measure your loaded rounds 'base to ogive' vs. 'base to meplat'.

Your point does have some validity though, if you are jumping your bullets .045", and you are using a very forgiving bullet (like the Berger 155.5), does it matter if you are off by an average of .006-.010"? Probably not. If you are using a more twitchy bullet (like a VLD), and are seating close to the lands, I submit that it makes a huge difference.

Personally, it doesn't take any more time to take a base-ogive measurement, so I pretty much use that measure all of the time. The only time I use a base to meplat measurement is if I'm curious as to whether a new load will fit in a given magazine.

my .02,

Darrell

 

[Greg Langelius *]

Re: Load Development Stage 2

Thank you very much Darrell. I appreciate your response. This gives me more info to work with. It all adds up and helps.

Greg

 

[b_4]

Re: Load Development Stage 2

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> Since you are going off COAL, would it be safe to assume you don't have any tools capable of measuring off the bullet ogive instead of the OAL?</div></div>

That is correct. I understand that my measurement is specific to my bullet.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> I would urge you to not try going anywhere near the lands based off that measurement. Again, I can't emphasize enough the need for the right tool for the job - something that measures the seating depth off the ogive of the bullet.</div></div>

Thanks, this kind of experienced feedback is why I posted!

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> Monte is absolutely correct, a comparator tool of some sort to measure seating depth off the ogive of the bullet is an absolute must.
.
.
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I have found that even the best competition bullet's base to meplat measurements can vary by as much as .015", therefore your 'perfectly' loaded rounds can vary by around this much. The base to ogive measurements only vary by .001 or .002"; generally a much more accurate way to measure your bullets, and by extension, your loaded rounds. It takes no extra time at all to measure your loaded rounds 'base to ogive' vs. 'base to meplat'. </div></div>
Thanks Darrell.

FYI, here are the results of my complete ladder test (Fired at 525 yards). 7 of the 9 loads were 1 moa or less, which is a testament to the Savage 12 F/TR's accuracy.

My monthly matches are at 525 yards but I do have the goal of shooting 1000 yard matches this fall once I am proficient at reading the wind at 525 yards. I would also like to thank everyone for letting me discuss this shooting adventure here and for sharing your knowledge. This is what makes shooting sports what they are.

 

[WhiskeyWebber]

Re: Load Development Stage 2

Nice Work! One suggestion... I would use the Median MV instead of the Average MV for planning your ballistics charts. It is just more statistically correct when you are dealing with the small sample sizes associated with load development.

 

[KYpatriot]

Re: Load Development Stage 2

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: b_4</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> Since you are going off COAL, would it be safe to assume you don't have any tools capable of measuring off the bullet ogive instead of the OAL?</div></div>

That is correct. I understand that my measurement is specific to my bullet.</div></div>

B4, just to clarify. Do you understand that what he is saying is that the critical measurement is lands to the ogive of each individual bullet? In other words, the base to ogive measurement will vary even within the same lot of bullets? Each loaded around could have a very slightly different OAL based on slight inconsistencies in the ogives of every bullet. If you have a comparator every round will have the same jump regardless of OAL.

If I am being redundant, my apologies, by your response I thought you may be assuming the ogive of every bullet in the box was the same.