How often do you test/tweak/change a load for a particular rifle?

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Roddy

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How often do you re test a load you have developed, either chronographing it, ladder testing against other loads, or even just shooting groups? Once in the life of the barrel? Seasonally? Every time you load a new batch?

I am just wondering because in everything I have read about reloading I don't think I have seen this mentioned much.


I chronographed a load I had developed last year in similar weather and I thought the readings seemed slow based on where I was hitting at longer distances (550 meters) and what my ballistic app was telling me as well as compared to last year (compared to the chronograph last year. I didn't shoot that far then so I don't know how different the drop would be.)

I don't know if my barrel is worn, my chronograph is damaged (I did hit one of the aluminum rods that hold up the sun shades with a round), or I'm missing something else.

I feel bad because I ask a lot of questions on this sub forum and get great answers but I don't have much to add. Thanks in advance anyways!
 
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Alpheus said:
What is the caliber and chronograph?
Click to expand...

It's a .308 shooting 178 A-Max's. Chronograph is a ProChrono Digital. It's not too fancy.

Last year I consistently got 2650 at about 5 meters so I called it 2665 at the muzzle. This year I got 2622 at 10 meters so about 2640 at the muzzle. The velocity spread is at the most 25 FPS over the nine rounds I tried. With the fastest and slowest taken out it the spread is 10 FPS.

My ballistic apps think I should be at 2675 FPS at the muzzle. I'm leaning towards his one because it gets me hits on target! I am inputting density altitude, wind, etc. Pretty much everything except the coriolis effect.

Everyone says you should have a chronograph but how much should you trust it? I know there are a lot of things that can couse the Err error message but can dust, lighting, or something similar cause a 20 or 30 fps error?

Oh and I level and bore sight the chrono for five minutes before I use it. It should be bang on that way.
 
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For an optical chrony, that is actually pretty consistent. I had Beta Chrony that changed upwards of 150fps between range days, thing was useless.

If you have a number that works, and your app gives you 1st/2nd round hits at long range, I would just roll with it.
 
Thanks Alpheus.

That does leave me wondering about my original question though. Do you need to adjust a load as your barrel wears and if so how often?

I have the components for about a thousand rounds with four or five hundred pieces of brass. Could my load deteriorate and need adjusting?
 
Chronographs lie. BCs are often lies. The adjustments of your scope might not be deliberate lies but the odds of them being the pure truth aren't exactly great. The ballistic program wont lie, but is no better than the lies being told to it. Targets don't lie.

So what to do? There's some things that you can prove. Pure drop can be measured. The accuracy of your scope adjustments can be proven at close range. If you are cranking 10 MOA and the scope is giving you 8 or 11 the program hasn't got a chance. In a world of lies the truth doesn't have a chance.

Sometimes its just easier to tell the program some little white lies, to force it to tell the truth. You can play with the BC input but that takes huge changes to change things. The big ones are velocity and the click value. Its hard on the head to plug in a velocity 100 off the chronograph even if it makes the lies align. Its somewhat easier to plug .25, or .26 or .23 per click on some programs, or on others you can decide that in your neck of the woods 1 MOA doesn't measure 1.045" but is actually 1.100, or 1". Whatever it takes to get you there.;)
 
Roddy said:
Thanks Alpheus.

That does leave me wondering about my original question though. Do you need to adjust a load as your barrel wears and if so how often?

I have the components for about a thousand rounds with four or five hundred pieces of brass. Could my load deteriorate and need adjusting?
Click to expand...

Shoot some groups and see. I'd do 100 and 300 meters/yards. If you kept the data from your load development, it is very easy to tell.
Few points:
1) 308 is a pretty long life caliber, 1000 rounds is just getting started.
2) base on anecdotal evidence, some barrels can change as they get well worn in, generally in the first 500 rounds or less. Tool marks and imperfections get worn away, pores in the steel get filled in with copper etc.

Before you start tweaking, consider the barrel fouling. Could be the barrel is excessively fouled? When was the last time you cleaned? Maybe you just stripped out the copper, and it is taking a while to lay it down again? My 6x47 takes forever to settle down after a cleaning, that's why I've only cleaned it twice so far.
 
Thanks for all the replies.

Alpheus I guess I should have been more clear. I really had two questions:

The first one, why is my chronograph different, you answered.

I am also wondering if my load will still be as accurate in 500 or 1000 rounds or if I should load smaller batches. There is nothing wrong with the rifle or load now.

Factory ammo never changes but I am hoping my loads are more accurate so that's a moot point.


I clean with G96 every 100 rounds or so and strip copper every few hundred rounds. It has about 600 rounds through it. I have a 6.5 Creedmoor barrel on order too.

I am almost done reading Applied Ballistics and while a lot of it is a bit over my head it really helped me understand just what is important and what isn't.
 
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Factory ammo does change from lot to lot...

Even when I have a consistently accurate load developed for a particular rifle, I double check POI before every hunt (not daily)... I want to have complete confidence in my loads accuracy... for the most part, I don't give a ratz azz about the velocity... I test for consistent accuracy.
 
I am always "re" testing loads. Environmental conditions are always different than the day you settle on your pet load. I recently found my front action screw becoming loose between groups, so I action and pillar bedded. The pet load may still be accurate but the rifle is now changed...so I will confirm and/or tweak to 1/4 MOA (rifle's capability).

Then there's component swaps and re-zeros before hunting season. Sooo...to answer the OPs question, I'm always playing devils advocate to keep a pet load a pet.
 
hoytcanon said:
Factory ammo does change from lot to lot...
Click to expand...

Yes I understand that. I meant to say they try to stay the same. If you're running say FGMM you can't just call up Federal and say "hey can you seat those a bit longer. My rifle shoots them better that way."

Thanks again for all the responses. Just when I think I have something figured out with this handloading/precision shooting thing I run into another variable. I just want to be able to develop a load that works well and shoot it all year with minimum velocity changes.
 
I have to teak my loads in my 6.5-06,not sure why,could be the weather,bullet lot or powder lot but usally .2 of a grain of powder up or down makes the difference.
 
Roddy said:
How often do you re test a load you have developed, either chronographing it, ladder testing against other loads, or even just shooting groups? Once in the life of the barrel? Seasonally? Every time you load a new batch?

I am just wondering because in everything I have read about reloading I don't think I have seen this mentioned much.


I chronographed a load I had developed last year in similar weather and I thought the readings seemed slow based on where I was hitting at longer distances (550 meters) and what my ballistic app was telling me as well as compared to last year (compared to the chronograph last year. I didn't shoot that far then so I don't know how different the drop would be.)

I don't know if my barrel is worn, my chronograph is damaged (I did hit one of the aluminum rods that hold up the sun shades with a round), or I'm missing something else.

I feel bad because I ask a lot of questions on this sub forum and get great answers but I don't have much to add. Thanks in advance anyways!
Click to expand...

Once I have a cartridge setup for a particular season, temperature and humidity I will leave it. Having said that loaders need to remember that one setup will not perform the same each and everyday due to the reasons I have mentioned. Plinking is far different then precision shooting that requires consistency. So if it is hot and hazy out I will select concoction A over B then when the weather changes during the day I will shoot concoction C. Getting there is very time consuming that requires patience galore but once they are found I leave them alone other then checking them.
 
I had just gotten into Precision Shooting Magazine, just before they went out of business, and there was an article about how the humidity levels of the powder affected velocity. It seems a few points higher or lower in humidity would affect velocity be a few feet either way.

I worry less about accuracy and recoil more than I worry about velocity. I check velocity to get in the ballpark, and double check powders, but worry more about accuracy.

But then I shoot lever actions, so my standard for accuracy isn't benchrest level either.
 
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