Thanks Saeed. Good work!

quote:

Originally posted by ANTELOPEDUNDEE:

quote:

Originally posted by Samuel_Hoggson:
Thank you, Saeed!

Looks like I don't need a series of expander buttons.

The "buttons" should be thrown in the trash can. Use a mandrel with a tapered end to keep the necks straight even if you need to expand as a separate step.

+1

Interesting test. But it's the results for one rifle........

quote:

Originally posted by JTEX:
Interesting test. But it's the results for one rifle........

Very true.

But, I am going to continue this test with 2 more rifles, in 22 and 6mm.

I will keep you all updated.

I am preparing a 6mm Norma BR next.

I have several rifles for this cartridge, I will let you know which one is chosen.

I have a Robler HV in 6mm BR Norma. It has a Leupold 6.5-20 scope on it, so that is the next to be tested.

As with the previous 308, I have not made any attempt to pick a particular load, so for this one I am going to use 32 grains of VVN135 with the Berger 65 grain bullets, in Norma brass, and RWS 4033 primers.

quote:

Originally posted by Saeed:
I have a Robler HV in 6mm BR Norma. It has a Leupold 6.5-20 scope on it, so that is the next to be tested.

As with the previous 308, I have not made any attempt to pick a particular load, so for this one I am going to use 32 grains of VVN135 with the Berger 65 grain bullets, in Norma brass, and RWS 4033 primers.

An interesting thing that I saw on another site that could affect neck tension is residence time or how long you keep the sized case in the sizing die before you pull it back out. The faster you pull it back out the more likely the brass is to try to spring back to the pre-size dimension which will depend upon the hardness of the brass.

Link to video.

https://youtu.be/sdJeADnU4Uk

I have finished testing the 6mm BR Norma.

I will post the results as soon as I am back home.

Currently out of the country.

Something else to consider. Load 4 rounds each at 3 different neck tensions. Have someone create a 4th lot of 3 rounds by taking one round from each group and mixing them up so you don't know which is which and see if there's a difference.

Any updates on this?
I'm eager to hear more on the topic.

Had not had time to finish this.

Will do in due time, but have no idea when.

Got all the dues and buttons, just too many things going on.

We are off on safari in a few days, and when I am back we have a new CNC lathe to set up.

Our 20 year old is getting long in the teeth, giving us too much hassle with parts.

Recently I trimed and necked down some 8x60 Mauser cases to 7x57 and the necks were really snug, I mean really snug, probably due to down sizing but additionally to the trim that was substantial to say the least, thus I inside neck reamed most, but I also loaded some as is (tight ones), some with outside neck ream, and shot all for accuracy..all using same load btw.

I could detect no difference in accuracy at 100 yards in my Win. fwt mod 70..I tried the same approach with a 257 Ackley and again nothing to write home about, I shot the 257 thru the chronograph and velocity difference with max 257 Roberts load (fireforming Ackleys) again no definable difference..Basically a waste of time was about all I could define..but not vary scientific, but what is scientific in our world of reloading, we fly by the seat of our pants..

Well come to think of it I did learn something of interest and that is the 7x57 and the 257 Ackleys didn't change POI enough to matter, so I could hunt with the either using fireform loads or maxed out loads..I am finding the same with my 8mm/06 Ackley that shoots the un-fireformed load, a max 8mm/06 load to the same poi as the Ackley max load but at a 150 FPS additional velocity, so I can hunt with either load as opposed to a waste of components and ammo. Money saved is additional, how much I don't know, don't really care, but lots of bullets and powder are saved I suspect..I fireformed 120 cases for Ackleys for elk, and 200 rounds are stacked up with 8mm/06 max loads for deer or whatever, that will fireform as I hunt and cull a bunch of Texas whitetail I suspect.

Anyway that's the plan..

How does a reloader measure tension?

F. Guffey

I don't think one has to measure neck tension other than by feel, that's getting over the top with "tech" You can feel the tension well enough to do "our" off the wall experiments to get good enough results..

When you pull bullets with the idea of replacing the load with another bullet or powder for instance, unless you "reneck" size them they will be loose to the feel, very loose in many cases...I have loaded them out of laziness that way, and Ihave resized the necks to get a good strong purchase of the bullet..both shot to the same POI in each case over the years, not just one case..

I still "feel better" with a re-resized snug neck, especially in a big bore as bullet set back from recoil is the catch, that is damned important, so I say tight necks are probably best..

quote:

I don't think one has to measure neck tension other than by feel, that's getting over the top with "tech" You can feel the tension well enough to do "our" off the wall experiments to get good enough results..

"You can feel the tension" I can't, I was not doing an experiment; 2 shooters/hunters needed a bunch of 7MM57 ammo, they failed to bring their cases. I form cases but did not have time.

I pulled bullets from my 7mm57 cases I had loaded for my rifles, my case neck 'tension' exceeded the ability of all my pullers meaning I rendered all of the bullets scrap. My case necks still had so much 'tension' I could not seat bullets with out resizing the cases. Same case, primer and powder.

They got back to Alabama, went hunting and then sent pictures. Of the 4 biggest deer they got 3 of them.

F. Guffey

yes thank you

We were having a discussion the other night about exactly this. If you have virtually no neck tension and bullet is free to move in case it will almost move out of the case immediately and then stick in the lands till pressure builds up and then it goes. I believe bench resters some times load with no tension and the bullet seated long so that it seats into the lands as the bolt is closed and the case has in effect been removed as a variable.

At the opposite end a decent crimp or firm neck tension provides a much more consistent release hence better accuracy. And from a practical hunting point of view I want consistency but don’t want bullets falling out of their cases in my pocket or in the magazine - learnt that lesson the hard way when trying a lee collet die with thinner walled ppu brass. Very little tension on the bullet.

Any indications on whether the changes in neck tension changed the muzzle velocity? The POI remained quite consistent from what I can see.

The most consistent method would be to breech seat the bullet independent of the cartridge case; the most accurate target rifles of the 19th century did that, and we still do it with artillery projectiles.
Sort of obviates the benefits of fixed ammunition though.

Saeed, Thanks for sharing your results. Lot of good research here. I appreciate it. Very interesting!
Brian

quote:

Originally posted by ANTELOPEDUNDEE:

quote:

Originally posted by Samuel_Hoggson:
Thank you, Saeed!

Looks like I don't need a series of expander buttons.

The "buttons" should be thrown in the trash can. Use a mandrel with a tapered end to keep the necks straight even if you need to expand as a separate step.

this! i am no longer a competition shooter but i have done this for years because, to me, it just makes sense.