*HELP!* has anybody seen where my accurate load went?

[philip140]

Hi guys, I need some advice here.

I went out last week to load test my Weatherby Vanguard in .243 with a batch of new Lapua brass (first time using it).

My load was as follows: Full length resized Lapua brass, Win LR primer, Hornady 87gr V-Max 5 thou off and Reloder 15 starting at 35gr working up to 37.5gr in .5gr increments. 3 shots fired at each charge.

Not exactly bench rest class load testing I'll agree but this is a sporter barreled hunting rifle I use for informal target shooting, varminting and deer hunting.

Now my problem is that I went out yesterday to test my chosen load for accuracy again and chrono the results, I was alarmed to find my load was shooting 2+'' 5-shot groups! mostly vertical I might add

Now I might be an idiot for doing this but I nearly always anneal brass after each firing as I find brass life is seriously increased, so as usual I turn my brass on a modified power screwdriver over a flame for a set amount of time (looking for cherry red) then size as usual.
I'm thinking that my annealing routine is nowhere near as uniform as Lapua's (duh!) and as such I am loosing accuracy due to inconsistent neck tension (pressure from seating bullets in virgin Lapua brass did seem a 'tad' more consistent).

Possible theories include:
1) The 'accurate' 37gr load I chose was a fluke good 3 shot group, successive shots would have shown poor grouping?
2) My annealing routine is in-precise and changes in neck tension from round to round is ruining accuracy.
3) Accuracy testing needs to be done on once fired brass vs virgin brass
4) The 2nd test day was 10-15°C higher leading to pressure changes pushing me out of the 'node'.

Original load test (yesterdays bad groups NOT shown):

note: shooting position, setup and distance (100yds) were exactly the same on both days. The rifle had been thoroughly cleaned and foulers taken both separate days.

Thank you in advance for any advice guys!

Phil

 

[Terry]

Some ideas...

Wind?
Re-Clean Gun.

I don't think these are it...

Possible theories include:
1) The 'accurate' 37gr load I chose was a fluke good 3 shot group, successive shots would have shown poor grouping?
2) My annealing routine is in-precise and changes in neck tension from round to round is ruining accuracy.
3) Accuracy testing needs to be done on once fired brass vs virgin brass
4) The 2nd test day was 10-15°C higher leading to pressure changes pushing me out of the 'node'.

 

[Mattm0812]

Maybe I'm missing something, but those groups are not bigger than 2"?

For a sporter barrel, those are not bad at all.

 

[LHSmith]

If you anneal cases until "cherry red"....consider yourself fortunate that you and rifle are still intact. THIS IS SO WRONG !

 

[necchi]

That's my take too, cherry red is way too hot, your neck tention is going to be messed up.
See if you can get your hands on some Varget, it's much less temp sensitive than RL-15.
I live in Minn, and Varget works nicely for hunting loads in all temps, I don't really need to adjust until I get to the extremes of 90 in the summer and -10 in the winter.

 

[philip140]

Terry – The bad grouping I got yesterday (not pictured) was pretty much all vertical ruling out the wind. The barrel had also been cleaned between both times and fouling shots taken.

Mattm0812 – Sorry for the confusion, the picture is of the original load test from last week, which went well. I did not include a pic of the terrible groupings from yesterdays shoot.

LHSMITH – : Relax, the entire case is not to go cherry red, just the case mouth then the case is removed from the heat source.

Necchi – A friend of mine does have some Varget not getting any regular use, I may try that once I rule out variables other than temperature.

 

[Terry]

Vertical in a load that shot great yesterday makes me wonder if the gun is jumping.

Retesting with brass you know is good would test the Brass theory.

 

[necchi]

LHSMITH – : Relax, the entire case is not to go cherry red, just the case mouth then the case is removed from the heat source.

Yeah OK, but cherry red at the neck is still too hot.

 

[philip140]

Terry - Good idea, I was thinking something similar. I will try loading the same load with some brand new Lapua brass, a couple 3 shot groups should confirm weather it's a brass issue. I don't know about jumping as the original load test with the decent groups were shot exactly the same way as yesterdays terrible groups, I use a home made front and rear rest.

Thanks, Phil

 

[philip140]

Yeah OK, but cherry red at the neck is still too hot.
[/quote]

If manually annealing like I do, what do you recommend looking out for in order to know when to remove from the heat? I think there are difficulties with waiting for a visual, as cherry red is an obvious and easy one to see in a dark room.

Phil

 

[Terry]

Sad to say, some days it's me.

 

[BoydAllen]

Some powders do not burn consistently without enough neck tension. It sounds like your necks are too soft. The way that my friend anneals is to use Templaq. He paints a thin stripe of 450 degree from the point of the shoulder down to the head on a test case, and keeps close track on how many seconds it takes for it to discolor down to where the annealing line is on a new Lapua case. To do this, both for testing and production work without the Templaq, he uses an inexpensive battery powered metronome, set on sixty beats per minute. This saves him having to watch the case and a timer at the same time. The system works well for him. Annealing has come a long ways from using the indicator that you have. The fellow that knows the most about this is Ken Light. You might look him up.

 

[6BRinNZ]

Did you anneal the new brass before load testing? If not I would rework your load on your annealed brass as a starting point. Its conceivable that your annealing is changing the neck characteristic (from how it behaves to new...Boyd has touched this) in a way that is significant for it not to work in that load....that's not to say that you can't develop a load for your annealed brass or that your annealing is wrong (it does sound like too much time and heat but who knows).

IMO to go from the groups in the picture to a 2" group (I assume this is 100yrds) typically takes a relatively significant change for the careful handloader.

The points you have listed, while they can and do affect accuracy and precision I wouldn't expect them to have this outcome. For instance I have compared brand new brass vs 3x fired brass for load accuracy over 200yrds in a 6br and while there is a difference it is nowhere near as significant as this issue.

What were your chrony numbers - did they vary much from the initial developed load? Chrony numbers don't mean much in themselves but they can be a useful guide if you have significantly different results on paper. If neck tension is the culprit, chrony numbers may well support that assumption.

 

[savageshooter86]

how long did you wait between shots/strings? I had a factory sporter barrel that would get very hot very quick and groups would open up like you talked about.

Are you shooting off bipod or bags or what?

 

[philip140]

BoydAllen Thank you for your input, I think you may be onto something there, neck tension issues from over annealing seems most likely. I am currently reading some articles by Ken Light, lots to learn!

6BRinNZ I did not anneal the factory fresh brass, just sized, prepped and loaded, I didn't want to ruin that picture perfect annealing line! I think i'll take your advice there, I'll finish off all the factory fresh brass, then once its all been fired i'll work up a load from my annealed brass (i'm currently making an annealing machine).

savageshooter86 Yes, I only ever take 3 shots one after the other then let the barrel cool down, with the temperature here in Canada right now, that doesn't take long!

Thanks for all the advice guys!!

Phil