Neck turning question.

[RonR]

I thought the point of cutting into the shoulder was to thin the shoulder/neck interface a bit to limit the formation of the donut?

Ron, I don't think the "ledge" your talking about is a problem....or at least I hope it's not cause I have 300 pieces of brass downstairs with it!!!!! Also, you need a target rifle....sorry man, but this much effort at the bench, and you're gonna burn up the barrel on your hunting gun!!! You don't have to spend 1000's, but something with a fat barrel that you can chip away at accurizing. ......bedding here, a trigger there

Oh, and don't forget that if you're carrying this ammo around hunting that some healthy neck tension is a good thing.....

For certain I am not a voice of experience at all, but based on that article from accurate shooter it seems text book GGG. The article uses the same neck turn system (K&M) that I am cutting my teeth with and is going to 1/32 depth. For some reason in my mind there is a distance that would prevent the donut from occurring yet when I compare cut angle of the K & M system to the angle of shoulder something in my head says that there will be a point at which the material will be thin enough to cause issue geometrically speaking <<< but I am certainly at no point to judge the article or for that matter what Bigbull and Yodave are sharing. They have the experience that I do not. I want to start in the middle and see what happens with the moderate loads we are using here.

Barrel wear? Shucks...I'll keep the Savage action and get something built on the rest of it. I like the trigger. You almost took the words out of my mouth with a good stock and bedding. This rifle is for me to learn on, as mentioned previously I liken it to to learning on my old 72 chevy and besides education and experience aren't always free and in this case it's ok to shoot the pi$$ out of it to get some wisdom. To me the competition gun load development thread is so interesting.

I kept an eye on my reloads last year in the field because I was really concerned but all the test's I put them through passed. Of course adjustment now is needed with the consistent neck size to maintain. I use a lee collet die...this bushing stuff seems somewhat complex to piece together and determine.

Apologies OP for continuing on. Bigbull and Yodave thanks for sharing.

Regards
Ron

 

[bearhunter]

Unless you have a chamber cut to minimum specs with a personal or custom builder's reamer IMHO there is little or no reason to turn the necks.

I have experimented, along with several others, to see if turning the necks makes any real difference in accuracy or extraction or anything else. What I have found is it make absolutely no difference. Some people claim it equalizes neck tension between rounds. Well not enough so that it is noticeable on targets out to 1000yds from what our tests showed on over 1000 shots fired with and without turned necks on rifles chambered in 308Win Palma Match specs.

I have an excellent 308 Palma Match reamer the was ground to minimum specs. With some brass the necks actually need to have a couple of thousandths of an inch turned off their diameters so that a loaded cartridge will chamber. Usually the necks with a bullet inserted have a .002 clearance over all. that is .001 all the way around.

The neck of the cartridge serves to control bullet/case tension for consistent burn of propellant as well as to center the bullet with the axis of the bore and of course they maintain a consistent distance off the ogive off the leade. In most HBR and other styles of match shooting the bullets are jammed tight against the leade but not always as each rifle is a different beast.

With custom chambers neck turning as well as special dies with carbide collars ground to take the necks down to diameters that will just hold the bullet and still have a couple of thou clearance are a must. The bullets are loaded long on purpose so that when the bolt pushes the cartridge ahead through its camming action the bullet comes into contact with the leade which helps to build pressures consistently and equally every time a cartridge is fired.

Back in the early days of cartridge development long necks were predominant to hold the bullets and to align the bullets with the axis of the bore.

Today, with such good quality brass available the long necks are no longer necessary. That doesn't eliminate the job of aligning the bullet with the axis of the bore.

Another thing common today with many hand loaders is the practice of neck sizing only. This is an excellent practice as it takes over part of the job of aligning the bullet with the bore concentrically.

IMHO turning the necks is a "feel good" thing in most instances. Not only that but by reducing the thickness of the necks you are also reducing neck tensions albeit you might be making them more consistent between cases.

The other thing is so many people insist on full length resizing their cases. OK, fine that doesn't make much if any difference to the accuracy of an off the shelf or even custom hunting rifle with relatively generous chambers. IMHO the practice of full length resizing or even partial resizing along with neck turning only enhances chances of poor bullet alignment with the bore, reduces neck tensions and creates difficult to pin point issues in accuracy.

Ok, I can understand cases that have been formed from a different parent case needing neck turning because often the necks on those cases will not have consistent thickness throughout the complete circumference. Sometimes certain lots of cases will have similar issues. IMHO this would indeed warrant neck turning.

IMHO again, is that if the necks are within a couple of thou of being of consistent thickness all the way around and feed without issues into the chamber of your firearm turning the neck only increases the tolerances that should be decreased and lead to inconsistencies which are detrimental to accuracy.

One reason match chambers are cut to minimum spec is to reduce tolerances and maintain consistency from shot to shot as much as possible. I have seen a lot of people turning necks with the idea that it will increase the accuracy of their hand loads. In my experience as well as that of many others this is just plain futile. If you don't have to make changes, don't.

 

[Gunneegoogoo]

Thx Bear. The insight into the history of long necks and short necks helps to explain in my head why somethings have gone the way they have in the reloading world....

One thing that I've wondered is what is the return on investment for turning. It's time consuming and expensive. I see your point, but I'm guessing from the little I know of Ron so far, he and I both would try it anyway..... It seems that the both of us like the journey - the techniques, the equipment, the learning - just as much or more than the shooting.... I recognize that sounds both sick and wrong, but I think it may be true!!!

Once I get my load perfected for my FTR rifle I'll join in on your turn/noturn experiment and report. There's a few other factors I'd like to try to contribute some science to as well. I know I'll be burning out my barrel, but I need the practice.....

I too have worried about the angle of the carbide not being correct. I've taken the thought that John at 21st century is an smart smart dude.....and "type A" enough to create this amazingly designed and fabricated gear, so it's unlikely he's wrong. I am going to split a couple of the cases I've f-d up to look at the shoulder thickness after my turning into the shoulder.

Ron, great thought about rebarelling your Savage. The savage 112 FTR is a very well respected target rifle. You could maybe do a build like that??? What caliber are you doing again??

 

[RonR]

Good read Bearhunter thanks for weighing in. I can understand what you have posted.

Will it make a difference in my shooting with my setup? Who knows. But some experience at the range and it should sort itself out. Like GGG states, I find it personally challenging to understand the science and put it into practice. Reloading has provided both higher shooting accuracy and confidence. If this does nothing than add to my confidence then I will take it. Perhaps this is like shiny brass for some...does it work better? probably not but does it make you feel good...you bet. ( I don't need to shoot shiny brass either )

One thing I did find however is that when seating bullets, OAL was inconsistent as well as the amount of force required to seat the bullet. I have a thread on it somewhere here. The reading I have done and upon suggestion by other Gunnutz is that a consistent neck thickness should bring consistency with that part of the process. (There are other factors as well perhaps such as brass hardness and inside surface smoothness etc causing extra friction plus a plethora of other factors... again I am a reloading novice so consider that in this response.) There has to be a relationship wrt force required to seat a bullet and neck tension causing different pressures... Taking the human equation out of shooting, if the rifle is the same along with ambient conditions from shot to shot, the difference would be cartridge to cartridge? <<< not meant for argument, just stating what I am contemplating out loud.

GGG it's 7mm-08. I haven't even contemplated any fancy rifle build...cause I would have to buy one I got to keep this to one thing at a time.

Regards
Ron