Reloading: what to tweak first?

[Duramaximos]

Happy thanksgiving!

I have some time to kill today at my reloading table, and about 50 rounds of 243, 65gr Vmax to load up.

I am thrilled with the results of my last load consisting of 40gr of IMR 4320, CCI 200 primers, and the bullets seated 0.020" from the lands. With this I acheived 0.75" 5 shot groups...my best ever from a centre fire rifle.

So my question is, where should I start my tweaking? I don't really want to change powder or bullets at this time. So my optoins appear to be increase the powder, or play with OAL. My only concern with increasing the OAL is this would result in the bullet not being seated very deeply in the case neck. At what point is a bullet not seated deep enough?

What would you do?

[6.5 shooter]

Primers; simple, easy and cheap. I have found better accuracy, more velocity and better groups, simply by changing the brand of primer.

6.5
Shooter

[t/c 25-06]

At what point is a bullet not seated deep enough?


From what I've read they recommend seating the bullet the depth of the dia. of your bullet, In your case 6mm. I just loaded a bunch of 55 gr. ballistic tips and there such a short bullet the closest I could get to the lands was 0.030". They shoot great thou, I didn't get out the calipers but there under 1" at a 100 yrds.

[Duramaximos]

Thanks for the suggestions guys.

Originally Posted by t/c 25-06

At what point is a bullet not seated deep enough?

From what I've read they recommend seating the bullet the depth of the dia. of your bullet, In your case 6mm. I just loaded a bunch of 55 gr. ballistic tips and there such a short bullet the closest I could get to the lands was 0.030". They shoot great thou, I didn't get out the calipers but there under 1" at a 100 yrds.

Since I don't have access to new primers today, I think I'll increase the OAL by 0.010...and maybe add another 1/2 grain of powder. I understand a longer cartridge will have less pressure, as long as it's not touching the lands, all other things being equal.

Cheers!

[catnthehat]

Originally Posted by Duramaximos

Thanks for the suggestions guys.



Since I don't have access to new primers today, I think I'll play with the seating depth...and maybe add another 1/2 grain of powder. I understand a longer cartridge will have less pressure, as long as it's not touching the lands, and all other things being equal.

Cheers!

Changing the OAL by as little as .005 can sometimes make a big difference on some rifles, not as much on others.
Once I get a decent load for velocity that is within pressure tolerances, I do ladder tests with the OAL to determine my accuracy load.
Cat

[Duramaximos]

Originally Posted by catnthehat

Changing the OAL by as little as .005 can sometimes make a big difference on some rifles, not as much on others.
Once I get a decent load for velocity that is within pressure tolerances, I do ladder tests with the OAL to determine my accuracy load.
Cat

Cat are you saying the OAL is the last thing you tweak? Do you think I should optimize the speed first? Would it hurt to do both in combination?

[catnthehat]

Originally Posted by Duramaximos

Cat are you saying the OAL is the last thing you tweak? Do you think I should optimize the speed first? Would it hurt to do both in combination?

Speed is a relative thing IMO, and I don't get too wrapped up in how fast I can make a bullet go in particular cartridge if it is not consistent.
I use my chronograph to find out the load with the most consistent extreme spread , moreso that the fastest. If the most accurate is 75FPS slower , so be it.
Some guys run their hunting rifles as fast as they can go, however, it's all in personal preference.

What one powder will do in a particular rifle is not always the best in another.
Once I choose a powder that gives me a decent velocity for the cartridge, I then run a series of tests with 5 cartridges usinf different OAL's in .010 increments.
Once I determine the best of them, I narrow it down to .005 increments.

On some rifles however, this cannot be done, as the magazine determines the longest OAL you can use.
Hope this answers your question.....
Cat

[elkhunter11]

I understand a longer cartridge will have less pressure, as long as it's not touching the lands, all other things being equal.

With rifle cartridges,the longer cartridge usually produces more chamber pressure.This is because,the closer the bullet is to the lands,the less momentum it has for the bullet to be engraved by the lands.

[Duramaximos]

Originally Posted by elkhunter11

With rifle cartridges,the longer cartridge usually produces more chamber pressure.This is because,the closer the bullet is to the lands,the less momentum it has for the bullet to be engraved by the lands.

This is the opposite of what I've read. But I understand the logic behind your point. I'll have to check a couple different references...

[elkhunter11]

This is the opposite of what I've read. But I understand the logic behind your point. I'll have to check a couple different references...

You can find documented proof at the link below.

www.shootingsoftware.com/pressure.htm
Follow down the page about halfway to the example using different seating depths.

Or you can simply prove it for yourself by loading up some test ammunition with different seating depths,and chronographing the loads.In my own testing,the loads where the bullets were closer to the lands, provided the higher velocities,as a result of the higher pressure being produced.

[gitrdun]

Originally Posted by Duramaximos

Cat are you saying the OAL is the last thing you tweak? Do you think I should optimize the speed first? Would it hurt to do both in combination?

You should only change one variable at a time. If you change both, you have no means of isolating which caused either your groupings to tighten or open up. If you're at a stage of reloading where you now have become so anal that you must improve on .75 moa (totally understandable), then a chrono might be the next tool for your bench.

[Duramaximos]

Originally Posted by elkhunter11

You can find documented proof at the link below.

www.shootingsoftware.com/pressure.htm
Follow down the page about halfway to the example using different seating depths.

Or you can simply prove it for yourself by loading up some test ammunition with different seating depths,and chronographing the loads.In my own testing,the loads where the bullets were closer to the lands, provided the higher velocities,as a result of the higher pressure being produced.

Thanks for the clarification.

I have a few grains to go before reaching max loads recommended by several sources, and I haven't observed any pressure signs yet.

I'll start my tweaking with the OAL next.

[Duramaximos]

Originally Posted by gitrdun

You should only change one variable at a time. If you change both, you have no means of isolating which caused either your groupings to tighten or open up. If you're at a stage of reloading where you now have become so anal that you must improve on .75 moa (totally understandable), then a chrono might be the next tool for your bench.

You're absolutely right, and I'm in no rush. Truth be told, I stumbled onto 0.75 moa accuracy almost right off the bat. Since I haven't put too much effort into this, I figure I'll try a few tweaks and see where it takes me. A chrono isn't in the cards this year, but maybe next.

[bobinthesky]

Originally Posted by Duramaximos

This is the opposite of what I've read. But I understand the logic behind your point. I'll have to check a couple different references...

This is the reason why Roy Weatherby free bored his barrels. It was to allow the bullet a longer jump at the lands in order to decrease the pressure spike after ignition.

As for maximum bullet seating depth, a lot of reloaders consider seating at least the diameter of the bullet to be max length. That is to say that a .243 bullet should be seated into the case at least .243 inches, a .308 bullet, at least .308 inches.
This asures that the bullet is seated parallel with the case walls and is aligned properly with the bore. I think that there may be merit to this but is likely not an absolute.

[whitetail Junkie]

Originally Posted by bobinthesky

As for maximum bullet seating depth, a lot of reloaders consider seating at least the diameter of the bullet to be max length. That is to say that a .243 bullet should be seated into the case at least .243 inches, a .308 bullet, at least .308 inches.
This asures that the bullet is seated parallel with the case walls and is aligned properly with the bore. I think that there may be merit to this but is likely not an absolute.

x2 about the depth of the bullet,well said

[378Canuck]

Originally Posted by Duramaximos

Happy thanksgiving!

I have some time to kill today at my reloading table, and about 50 rounds of 243, 65gr Vmax to load up.

I am thrilled with the results of my last load consisting of 40gr of IMR 4320, CCI 200 primers, and the bullets seated 0.020" from the lands. With this I acheived 0.75" 5 shot groups...my best ever from a centre fire rifle.

So my question is, where should I start my tweaking? I don't really want to change powder or bullets at this time. So my optoins appear to be increase the powder, or play with OAL. My only concern with increasing the OAL is this would result in the bullet not being seated very deeply in the case neck. At what point is a bullet not seated deep enough?

What would you do?

Do the Audette ladder first. Then proceed with what your doing now.

[silver]

When it comes to finding the best group, I would work on the powder first. I would take a bullet/powder load, load five of starting load, go up one grain and load five more and so on until max.I would find the first group would be kinda wide, like several inches. As the the powder wt goes up, the groups would drop and then start to increase in size. At this point, I would go back to the load that shot well and load three more, five at the good load, five at half a grain under and five at half a grain over. If you can get your hands on benchrest primers, then by all means, try them. The oal didnt make that much difference for me, but go ahead and try. Good luck and good shooting.

[303carbine]

Originally Posted by Duramaximos

Happy thanksgiving!

I have some time to kill today at my reloading table, and about 50 rounds of 243, 65gr Vmax to load up.

I am thrilled with the results of my last load consisting of 40gr of IMR 4320, CCI 200 primers, and the bullets seated 0.020" from the lands. With this I acheived 0.75" 5 shot groups...my best ever from a centre fire rifle.

So my question is, where should I start my tweaking? I don't really want to change powder or bullets at this time. So my optoins appear to be increase the powder, or play with OAL. My only concern with increasing the OAL is this would result in the bullet not being seated very deeply in the case neck. At what point is a bullet not seated deep enough?

What would you do?

I seat the bullet where it is obviously too long, chamber the round, then keep seating till it fits. Once it does, then give the seater die another 1/2 turn down. You can try the black marker after and see if it touches.

[catnthehat]

Originally Posted by silver

When it comes to finding the best group, I would work on the powder first. I would take a bullet/powder load, load five of starting load, go up one grain and load five more and so on until max.I would find the first group would be kinda wide, like several inches. As the the powder wt goes up, the groups would drop and then start to increase in size. At this point, I would go back to the load that shot well and load three more, five at the good load, five at half a grain under and five at half a grain over. If you can get your hands on benchrest primers, then by all means, try them. The oal didnt make that much difference for me, but go ahead and try. Good luck and good shooting.

I have to disagree with the OAL not making as much difference as powder.
these two ten shot groups were thrown charges, not weighed, and the difference can be easily seen.

The aiming point was the same ( the lower one) and the shots alternated , one shot each group ,to remove as many variables as possible.
The cartridges were all loaded long then the OAL set before each shot, then the scope setting moved to the next shot.
As you can see here, .010 can make a substantial difference .
Sierra also says to go to a mid range load first and after you find the most accurate OAL then mess with the powder.

The high shot was a called flyer, BTW.
Cat

[378Canuck]

This group was shot at 300yds with thrown charges. .223 mini ruger target barrel.
I chronographed them with speed spreads in the 50-70 fps diff with MV of 3125 fps.



Too show you I'm not BS. blasting through the screens. The log pile is at 100ys and the far bush line is 304yds lasered with swaro. The black pile over the tail light is where the drum is.

[elkhunter11]

Too show you I'm not BS. blasting through the screens. The log pile is at 100ys and the far bush line is 304yds lasered with swaro. The black pile over the tail light is where the drum is.

I myself would not post pictures showing a firearm being fired off of a motor vehicle.The interpretation of having a loaded firearm in/on a motor vehicle,can be interpreted differently by different officers.I had one officer check firearms leaning on or against a motor vehicle to see if they were loaded,and after discovering that they were not,he informed me,that we could have been charges if any of them were loaded.

[378Canuck]

No worries, this is about 70 miles from nowhere on gravel road. This gravel pit has been used for shooting for over 30 years. Officers don't do this gravel road and even if they did it would be to join me in a shooting competition and I would kick their asses same as I do at the range. I forgot to mention- Icall the bottom hole a flyer. LOL

[catnthehat]

FWIW, when we talk about working up loads, it should be considered and taken for granted that we are doing this in a rifle that is already accurized.
That is, the bed is good, everything is tight on the gun, and the scope is already proved to be accurate, etc.
Without these things a 9 shot .250 MOA group at 100 yards or 300 yards with a flyer that opens it up a touch cannot be properly evaluated , nor can the load development.
Cat

[gitrdun]

Cat nails it down once again, wouldn't expect anything less. In my own experience, the "once flyer" I often attribute to my very own trigger pull. When the flyer occurs, I simply cannot leave the range until I've established that I'm not such a "flawless" shooter. We all do it, pull a shot, but in most cases, I can call a bad shot and tell you which direction it's gonna go. And this is the reason why we get so addicted to shooting, it's a drug.