Help interrupting finding

[bfm1851]

So I just recently purchased a set of Hornady Matched bushing dies on the exchange. From all I've read on the internet that is the nest step to get my ES and SD down for longer range shooting. Loaded up three groups of 10 rounds each of 6.5 CM using 140ELDM and 41.2 gr. of H4350. Brass is Prime brass. Also started to clean with SS pins and water (if that makes a difference)
Started by measuring about five fired cases. Shoulder measured 1.561

Group 3 was tumbled with corncob media and FL sized with Lee die, trimmed to length using Lee trimmer. Measuring the case to shoulder length was 1.550. Deburred inside and outside of cases, loaded with 41.2gr H4350 trickling last 0.001gr. Bullet seated with Hornady micrometer seater to 2.235 CBTO

Group 2 was cleaned with SS pins and water and sized and loaded as group 3. I di not use and lube when seating bullets but nothing felt hard. I have been told you should either lube bullet or inside of case neck when cleaning with SS pins and water. (?)

Group 1 was SS cleaned but was sizes with Hornady FL bushing die using 0.289 bushing. I adjusted till I got a shoulder bump of 0.003 or 1.558. Neck OD was 0.290 and ID was 0.263. I had used the elliptical expander when sizing and it measure 0.262~0.263. I later read that I might should not have used that expander with the bushing die(?) I did lube bullets some with unique case lube. Just got some on my hands and rubbed bullets a little.

Anyway off to the range I went. These are 10 shot groups shot at 100yrds off bipod and rear squeeze bag. I shot slowly trying to keep barrel cool and had to stop and couple times to let things cool back down. It's East Texas and temp was only about 88, wind was about 8mph from the NE. Target is located almost north of bench.

I was expecting group 1 to have lowest ES and SD but that was not the case and it was the slowest avg. MV of the three.

What am I doing wrong (or right) and where should I go from here? Longer range? Larger groups?

Thanks in advance.

 

[nn8734]

I do all load testing at 300 yards. It’s real easy to shoot a tight group at 100 (you almost have to shoot a bad group on purpose). Thus when measurements and group sizes don’t seem to agree, it creates confusion, like yours.

Shoot the groups at 300 (then the best performing load at 600). That will give you a much better idea about how tight your load’s vertical dispersion really is, which is what SD/ES ultimately predict, all other things equal.

 

[918v]

Group 1 had the least bullet pull, hence the lowest velocity due to the less efficient combustion. If you get a tighter bushing then you’ll get similar results to Group 2 and 3.

 

[bfm1851]

I was not really worrying about group size as this is a known load for this rifle and groups well out to 300yds. That is the farthest distance I've shot for groups. Was tiring to see what advantage I get when I size with bushing die as oppose to regular FL die. I shoot steel out to 800yds but its hit and miss. Figure its the loading process (maybe shooter )

I'm doing all velocity measure with a Magnetospeed so I don't see how increasing distance will change numbers any.

I kind of agree that group 1 would have a bit more case capacity as shoulder is not bump back as far as others but only by 0.003. 918v is that what you are referring too by bullet pull? I could increase charge a bit to see if that helps but what I am concerned with is the ES and SD. I read where everyone (some anyway) are getting single digits and think that has to help the farther out you shoot?

Do others that clean with SS and pins lube bullets or case necks to help make neck tension more equal?? Read so much about carbon residue and all. You can really get lost chasing this stuff from the internet. Never know who is give the advice

If this matters rifle is an old Savage .308 that I swapped out the barrel to 6.5. 24" or there about. I have always though of myself as a decent shooter but that changed quick when you get our past 300yrds.

What next? reshoot at 300yrds? Drop out the corncob tumbled cases as I don't have any more and tumbler is broke. Bought a FART so I'm going in that direction now. Any help there would be appreciated also.

 

[918v]

No that’s not what I meant. For one, case capacity is relative. It depends on the chamber size, not what you bump the shoulder to. When you measure case capacity you measure fired cases that conformed to your chamber, not sized or factory fresh cases.

Second, what I meant by bullet pull was related to your case sizing process. When you use a bushing die with a maximum diameter bushing you are not sizing the neck very much. A standard FL die sizes the neck a lot more and this does two things: 1. It work hardens there neck more and 2. It induces more spring back in the direction of the bullet, even though the expander sets the neck tension to the same diameter as your bushing die. This, in turn, increases seating pressure and results in more bullet pull. If you were to try pulling those bullets you’d see they’re in there tighter than in your bushing sized rounds. Because of this increased bullet pull, you end up with more velocity.

 

[bfm1851]

Okay just finished reading another thread on bushing and mandrel dies. Seems I don't really know much about this. For many years I've loaded ammo with my Lee dies and thought I did real good when I purchased the four die ultimate set of dies. I have always shot well or well enough for the group I shot with. Now I am expanding my range so to speak and trying to explain some of those flyers I get.

So I thought maybe time for better set of dies. Bushing dies was what I thought would help the most but apparently I am not using them to there fullest. I now believe from what I read (918v most you wrote) that its should maybe be a two step process.

Step one size case with correct size bushing die, Sizing neck maybe 0.004 under size from measure loaded round which in my case is 0.291.

Step two is then resize neck using mandrel die to maybe 0.002 under bullet dia. This is a starting point as my rifle may like something different then 0.002 neck tension.

Is this pretty much what I should be doing?

In my test when I used the bushing die I had the elliptical expander installed and I am not sure at what point I was sizing OD of neck and ID of neck. I believe what happens is OD of neck gets size to bushing diameter on up stroke of ram and ID of neck tis sized on down stroke.

The mandrel die would size the ID of neck on the upstroke of ram. Pushing the mandrel down thru the neck would cause less working of brass then pulling sizer up thru neck. So next purchase would be mandrel die with a couple different size mandrels. 0.261-0.263

That right?

Reason for using bushings would be to control the amount of work being done to neck. In other words lessening the amount you close up the neck, right?

I am trying to get my head around all this and in the end it may not help me much as my abilities could be the limiting factor. But I would like to know where that point is.

Thanks

 

[spife7980]

You seem to be getting your head wrapped around it pretty well. You can buy different mandrels to test if you want. General rule of thumb is that an expander mandrel will be .001 under the bullet diameter, a turning arbor will be .002 under bullet diameter and that arbor is actually what most people are using. They are both generally the same thing other than the .001 difference, just labeled with different terms in many places due to them both originally being used for turning necks vs just setting a diameter for loading. The expander mandrel actually acted as a mandrel in that you forced the brass around it to form and the arbor was just small enough that it was still a tight fit but didnt actually change its size and the brass would just spin around that arbor whil the turner cut instead of being forced over it changing the inside diameter.

Bushings allow you to limit the amount of over working done to the brass vs a normal die that takes it all the way down past whats necessary.
Honing a normal die neck diameter can result in the same end result, you just cant put that material back once removed for thinner brass where you could just swap a bushing to whatever you need.

Mandrels and expander balls will do the same thing as well. Its just the mandrels seem to result in a more consistent results due to brass having a higher compressive strength and geometry to resist bending off center when the mandrel is pushing in as opposed to the weaker tensile strength properties of brass with the expander ball pulling out. The mandrel also leaves the entire neck in contact with the mandrels diameter for longer vs the expander ball thats only touching a smaller part of the neck and usually not all at the same time so the mandrels leave a more consistent result due to that as well.



My issue in your test is that its not really a completely representative test of what happened. When you change something you alter the whole system, Id test a wider spectrum of charge weights to see a more complete picture of what the change in your process really had.
Yeah group 1 had a higher SD but maybe if you added a tenth of powder you would go back up to the 2765 fps region where the SD comes down but not open back up like group 3 did. Or was it just that one flier out wide that threw your sd negligibly higher or did you pull it? There is a lot of unanswered questions with only 3 disparate data points.

 

[smoothy8500]

But I would like to know where that point is.

The goal for small SD's has their place, but I think some people make too much of it. Here is an example of a 308 load that I tested for F-T/R at 1k just to see what happens. The load has decent groups at 300yds but by everyone's standards an "atrocious" ES over 50 fps:
I was only concerned with holding for elevation, not wind. SD's at target were 35 fps. Won't make great NRA scores, but all stayed within the target.

 

[bfm1851]

spife7980, in group 1 the second shot was the flyer. I saw it go wide. Went back thru data on Magnetospeed and if I delete the second shot,
average MV = 2745
ES = 14
SD= 4.72
The second shot muzzle velocity = 2764, must have been an error on my part during charging or seating.

This is much closer to what I would have expected using what I used.

Next step I suppose is to load up more and test again to see if numbers bear out. Also raise charge weight a couple 1/10 to see if velocity comes up.

Then I can look into getting a mandrel die and a couple different size mandrels.
My fired brass neck OD measures 0.295
Fired brass shoulder measures 1.561

I uses a .289 bushing but have a .288 bushing also. Should I try both to see if it makes a difference even if I only have one elliptical expander which measures 0.263~0.262?
Very interested in your input here.
Thanks

 

[spife7980]

You can try all the different little things to get the very best. Just realize that it might not net you any improvement and what improvements they do offer could be very small. I like to stick to one standard set up and just let the powder charge and seating depth be my variables that I change.
If I were to experiment I would fully sort out the results that one system gives first and then compare how that one change effected it. Altering 2 variables at once inevitably leads to more questions then answers and takes 2x as much testing to go back and figure out.

 

[acudaowner]

I am getting the feeling you were thinking about a snake on the first group of shots the second makes me think of African fertility statues you naughty puppet , and the last shots a fear of conformity you had all the previous shots in a hole and it made you think no I have to sabotage a good hole by adding another just to the right like a golfer that leaves his shot dangling on the edge of the cup .