DILLON 308 REPEATABILITY ISSUES AND QUESTIONS - PLEASE HELP IF YOU HAVE SOLUTIONS!!

[bubbapug1]

Accuracy....that elusive thing. I have a Tikka that is shooting .4" groups at 100 yards using 168 SMK's and 44.0 grains of TAC. I want to close it up to 0.3" and than I will be satisfied...well, I hope I will be satisfied.




I really am seeing how variable a Dillon press is with regard to OAL, powder charges, etc.

I am loading 308. My brass is dead on in trim length and head spacing. Very little if any variance.

However, my press activities do vary.

My charge weights vary + 0.3 AND -0.1 grains using TAC at 44.0 grains. I am super careful to run the press eactly the same way from case to Case, no additional vibration etc.

My OAL varys +/- 0.015!! And that's with SMK's 168 grain....What could be going wrong with that process? I am using a Forester micrometer benchrest seating die. I crimp in the next stage with an RCBS die, but the variance is in the forester station. The crimp die doesn't change the OAL's at all.

I have a box of 308 I will take to the to test OAL versus group sizes.

Its a run of 80 rounds and my OAL varied from 2.760 to 2.780...same brass, same bullets...and I will see what results I get from each length...if the darn wind doesn't vary too much that is!!

[yakmon]

For the oal, try tightening the shellplate some more

[thmpr]

This will not help the inconsistent OAL. But I too wanted to tighten my groups to .5. I've tried everything from tightening up the dies, cleaning the dies, and even tried different types of dies. At the end, the trick was to go with a different powder - Varget. The load I use is 44.2. Please use it at your own risk.

[Bill Steele]

Lots of questions, but I guess start with one...

Accuracy....that elusive thing. I have a Tikka that is shooting .7" groups at 100 yards using 168 SMK's and 44.0 grains of TAC. I want to close it up to 0.5" and than I will be satisfied...well, I hope I will be satisfied.

I really am seeing how variable a Dillon press is with regard to OAL, powder charges, etc.

I am loading 308. My brass is dead on in trim length and head spacing. Very little if any variance.

However, my press activities do vary.

My charge weights vary + 0.3 AND -0.1 grains using TAC at 44.0 grains. I am super careful to run the press eactly the same way from case to Case, no additional vibration etc.

My OAL varys +/- 0.015!! And that's with SMK's 168 grain....What could be going wrong with that process? I am using a Forester micrometer benchrest seating die. I crimp in the next stage with an RCBS die, but the variance is in the forester station. The crimp die doesn't change the OAL's at all.

I have a box of 308 I will take to the to test OAL versus group sizes.

Its a run of 80 rounds and my OAL varied from 2.760 to 2.780...same brass, same bullets...and I will see what results I get from each length...if the darn wind doesn't vary too much that is!!

Are you using a comparator to measure your OAL?

[bubbapug1]

Are you using a comparator to measure your OAL?

No, I use a micrometer. I realize there may be difference in the bullet shapes which may result in the die pushing one bullet in farther than the next one, but I didn't think they would be as extreme as 0.020 in difference.

I also have tried Varget, and the TAC works better in this rifle for me at least. Also, a dillon meters TAC better than varget as its a volumetric filler cavity, and Varget is harder to pack consistantly into the pocket than TAC, which has superiour flowability.

I was thinking about inducing a constant vibration to pack the powders to the maximum to try to alleviate the powder variance.

[StaTiK]

Are you using a comparator to measure your OAL?

No, I use a micrometer. I realize there may be difference in the bullet shapes which may result in the die pushing one bullet in farther than the next one, but I didn't think they would be as extreme as 0.020 in difference.

So how much of the variance comes from the bullet profile and how much from the press? Until you get the comparator you'll never know. Get a comparator and go from there.

-StaTiK-

[TMC]

The Dillon will only be consistent when you have cases at all the stations so there is equal pressure on the shell place. You can also add a higher quality toolhead and Toolhead Clamp Kit that bolts it tight to the press to eliminate movement.

[joelogic]

So if a progressive press can get a .7" group when do all the fancy toys in the Sinclair catalog come into play. Meplat trimmer, neck reamer, bullet jacket thickness tester, concentricity measuring tool, micrometer seating die, annealer?

Variations of .1 gr in case and bullet weight?

I thought someone posted here about a guy shooting a record group at 1k by annealing and neck sizing the same piece of brass for the whole 10 shot string.

[Bill Steele]

There are any number of factors.

Are you using a comparator to measure your OAL?

No, I use a micrometer. I realize there may be difference in the bullet shapes which may result in the die pushing one bullet in farther than the next one, but I didn't think they would be as extreme as 0.020 in difference.

I also have tried Varget, and the TAC works better in this rifle for me at least. Also, a dillon meters TAC better than varget as its a volumetric filler cavity, and Varget is harder to pack consistantly into the pocket than TAC, which has superiour flowability.

I was thinking about inducing a constant vibration to pack the powders to the maximum to try to alleviate the powder variance.

The comparator is the only way I know, to know if your bullet is being seated consistently. Even more importantly, it measures the distance you care about (how far from the lands the ogive sits when the round is chambered). You don't care where the points are, just the ogives.

Since you are crimping, I assume you are shooting from a semi like an M1A or LMT?

Why not trickle each round for a while, til you decide the variances you might be getting in your drop is not the main factor in your groups?

[Wrangler John]

Consistency

As an earlier poster said a bullet comparator should be used to set seating dept. Most bullet manufacturers mix bullets from several die sets so the length varies. Also, bullets vary by tip length, especially hollow point styles, while the distance from the base to ogive are fairly consistent. When I swagged my own jacketed bullets in custom dies, the bullet lengths were spot on, because each jacket was trimmed to length and all operations used the same die. IIRC, Berger bullets are packaged without mixing. Those that I measured are consistent within +/- .001" with a few running more or less.

However, your seating die isn't (or shouldn't be) seating with contact on the tip. The seating stem should be contacting somewhere near the ogive/shank junction. Use a Sharpy to blacken a bullet and seat it, that should tell you where contact is happening. A seating stem can be returned to the manufacturer with a few sample bullets for adjustment.

There isn't a progressive press made that will produce the precision that you are looking for. Most progressives, I have two of different brands, will shed powder kernels as the cases move away from the charging station and stop at each subsequent station (RCBS Pro 2000 was the worse with a detent ball spring that would snap into the shell plate with enough force to kick kernels out of the cases. When I asked about this they changed the spring tension and sent me a replacement). When I was at Nosler last year I asked if they had a similar problem in their custom loading operation (they use Dilon presses) indeed they did, to solve the problem they mounted bristle brushes at the stations after charging to prevent case shake. If you see kernels of loose powder on your press this is occurring.

Your charge weights are within the tolerance range of most commercial powder measures, especially those with a case activated drop system. Believe it or not, that shouldn't make a huge difference in accuracy with a factory rifle and roto-forged barrel. Try running a small quantity of pure powdered graphite through the measure (collect it back in the container for reuse) this will break any static charges and lubricate the drum and drop tube. if the measure doesn't have a powder baffle inside the reservoir, place a funnel on top of the reservoir and keep it filled with powder to act as a baffle.

For maximum accuracy each case should be checked for primer pocket depth and contour, by using a Sinclair uniformer. Then the flash holes deburred. Progressives are piss-poor for maintaining primer seating depth as the shell plates have too much flex. I prime cases with a hand tool (the RCBS and primer strips works well) and never use the press. Also I size using a single stage press to maintain dimensional control. The progressive is used to load and seat only - crank them out fast. These loads for .204 Ruger, .223 Remington, 22-250 Remington, .243 WSSM, and .257 Roberts AI all shoot under .5".

Also check that your action screws are set to factory specs with a torque wrench, this can absolutely make or break accuracy.

[Hogxtz]

. toolhead and Toolhead Clamp Kit that bolts it tight to the press to eliminate movement.

^^^^^THIS workwed great on my Dillon. My OAL and trim length are near perfect now. This clamp kit solidifies the tool head to the frame.

[bubbapug1]

I took 20 cases over to my RCBS single stage 50 bmg press and loaded of few bullets on them. Again, variation of between +/- 0.005" So its not the press. I will buy a comparator to see if its the bullet profiles causing the issues.

Its not point to back, its Ogive to back correct?? I can see variations with my eye ball which will cause 0.005" variation on the SMK points.

[Sub95]

""Its not point to back, its Ogive to back correct?? ""

correct.

on my single stage i seat them higher to start off with and will go back through them and set them to the height i want them, yes i measure every one of them. but i get 3 shot groups under .300" out of my .308

[Bill Steele]

Hundreds of factors go into consistency.

I took 20 cases over to my RCBS single stage 50 bmg press and loaded of few bullets on them. Again, variation of between +/- 0.005" So its not the press. I will buy a comparator to see if its the bullet profiles causing the issues.

Its not point to back, its Ogive to back correct?? I can see variations with my eye ball which will cause 0.005" variation on the SMK points.

Yes, without a comparator you don't know how much of the variance is the press and how much is the bullets.

OAT, Raymond has a bunch of videos on his Dillon setup and as I recall he points out one of the kits he uses to keep the toolhead solid when reloading, that has got to help with OAL consistency as well.

In the end, there are lots and lots of things that go into accuracy. I think it was the "uscbigdawg" that posted shots of an obliterated quarter he did with a .223 (I think) at like 300 yards (I think) and that ammo was loaded on one of his Dillons, so amazing accuracy is possible from those presses.

[GeoffLinder]

.7 MOA from a progressive is pretty good. Better tolerances may not make the difference you are looking for.

The best way to shrink group size once you have a pretty good recipe going is to run charge ladder tests with powder charge varied in .2 grain increments until you find the barrel velocity node for that load. If you have not done this already to arrive at the recipe that gets you .7 MOA then no amount of fiddling with charge and OAL is likely to get you any better until you actually find the velocity the barrel likes. THEN you start playing with OAL and other fine points.

Bughole groups are 50% about process consistency and 50% about finding the velocity that is best in that barrel with that set of components. Sounds to me like you need to focus on finding a barrel node first here