Accuracy Limitations of Progressive Presses?

Mauser GDog

Mauser GDog

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I can't stand the cost of shooting factory ammo any more, and at times I can't even find what I want in stock. It's time to take the reloading plunge.
I've read some manuals and I think ;) I'm ready to start shopping.

I want to get more serious about my practice, and as a result, hopefully become more competitive.
I am approaching reloading as an extension of my favorite hobby (shooting!) and I have a fair amount of free time to spend in the gun room.

I'd like to produce annually a minimum of:

5000x 62gr .556 @ min 2MOA
500x >62gr 5.56×45 at the highest quality ammo I can achieve

2000x 150gr 7.62x51 @ min 2MOA
200x .308 hunting ammo at the highest quality I can achieve

My question is, what if any sacrifices in accuracy existing when using a progressive press -vs- a single stage press? Assuming all presses and loading components are of the same quality.

The seemingly obvious answer may be buy a progressive AND a single stage but I'd like to hear opinions on the limitations of a progressive press, if any.

Thanks!
 
As you are quite likely aware, Your ammo is dependant on what you feed into the recipe (quality of brass, bullets, powder and primers), the consistancy of those individual components, and the care that is taken in assembling them.

There is a lot of belief that a press offers up accuracy of a finished round, and that by their nature, progressives have too much 'slop' or variation in the tolerances to make quality ammo.
I don't think it does. Afterall, what is a press offering other than mechanical advantage to get components in and out of the dies?
For both brass sizing and bullet seating, the bulk if the work is done correctly or incorrectly in the die.
What metrics are we comparing for work within the die? Runout and OAL. I've got some Redding and Forster match dies in .223, .308 and 6PPC. I've measured both Runnout and OAL on a fair comparison of rounds created on a Rockchucker and my dillon machines, and can't say there is significant difference. If the press is putting the brass ####-eyed into the die, that is going to create inconsistant ammo, be it coming out of a single stage or a progressive.
With a progressive press, you can pick and choose some of the steps to hand loading that are done on press. For example, it may make sense to remove stuff like powder throw/drop/trickling and primer seating from this process if the handloader is looking for more control over consistency.
 
.in stock configuration , even a good machine like the XL650 isn't perfect regarding consitency of the AOL and powder drop weight. discrepancy in the order of .010 from round to round isn't rare .

it still has to be mod'ed a little with more accurate add-ons like a good powder drop bar assembly (like the arredondo unit ) and a good set of comp dies. another factor is the powder used. some meters poorly whatever the powder bar used. everything flakiish-cylindrical powders can give you quite some variations.

all that said, rifle cartriges are know to be more finicky to load on progressives, resizing being a core .
 
my dillon 550 is awesome. the dies can be a ##### to get set up properly but once you do they never change. mine works awesome, so far i load 9mm and 45 on it. soon to be adding .38spl and possibly .300 win.
 
On the 650 there are some tricks for loading really good .308 ammo...

Some/all stick powder won't throw worth a crap in the powder measure so it's better to bring the case up into hole #3 and use a funnel to charge the case with a measured charge from a scale or charge master..

Make sure the seating die is set firmly into the shell plate or you'll get lots of OAL length variation

For machine gun quality blasting ammo CFE .223 can be used for both .223 and .308 with charge variance sub .1gr and will easily meet 2MOA criteria... In my 650 it's a lazy afternoon to roll up a months wages in components...


....trick is to find the components you need rite now ;)
 
silverfoxdj said:
Some will say the Forster single stage will be slightly more accurate as the dies self center themselves.
Click to expand...

You do realize that there is enough movement designed into the majority of shell holders and plates regardless of brand or type to allow the brass case to self center in the die right?
 
5,000 annually isn't as much as you'd think. Lots of target shooters shoot more than that. However, the press used doesn't mean anything. Your loading techniques are far more important. Particularly how you weigh the charges.
 
Since your only loading rifle and loading 7700 rds annually a single stage is the best way for you and save some money for initial setup. That's all I've used for over 30+ years.
You can always buy a progressive down the road if you think you need it.

Factory ammo may be difficult to find, but so are reloading components too. Either way it's getting tougher these days.
 
I found out how sloppy progressives are after running a single for years. My COAL would be -/+ .001 on a single and is as high as .01 on my 650. I spend a lot of time redoing ammo on account of my extremely picky attitude towards my finished product. I have found that sizing/depriming cases ahead of time helps a lot.
 
beltfed said:
sounds like your shell plate needed adjustment.
Click to expand...

To some extent I think something like a higher variation in COAL is going to be unavoidable. A shell plate moves on a pivot and has SOME play. Also the casings in each position are not directly supported by the ram so while it's not much the flexing due to loading in the plate is another variable that isn't there with a single stage. Differences in the resistance at different stations as it loads different brass will cause the plate to tip and flex in different ways. So on this one aspect alone I suspect that there's going to be some higher degree of COAL variation on a progressive. With fine tuning it's possible to get this down but it'll never be as low as a single casing shell button mounted directly on the end of the ram.

I might be wrong but from considering the 2MOA loading I think this is doable on a well tuned progressive with the right powder in the right powder measure.

But for the best accuracy the charges really need to be individually weighed. At the very least that means taking off the dispenser and replacing it with a cap which holds a funnel to allow the weighed charges to be dropped into place.

A risk with the progressive is that the case in the charging station MIGHT be missed with all the weighing steps going on or if there's an interruption. And the nature of the progressive loading makes it tougher to check for empty cases. That along with possible tilting and flexing issues with the plate makes me think that the best and safest method for highest accuracy ammo is going to require a good single stage press.
 
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I have made small volumes of my best quality ammo using a single stage press.

I have made large volumes of quality match grade ammo using a Dillon 650 and a 550. They key was using ball powder, since it metered perfectly. For many purposes, this match quality ammo would be good enough. This was made with surplus Berdan primed military cases. Commercial cases might have produced a better result.

This is a test group fired at 520 yards from a rail gun.

RAILGUN308AT525.jpg
 
Wow, this reloading forum is amazing, thanks guys.

So far it sounds like 2x of the most important factors are not press related:
1. die quality
2. powder charge consistency

I had been considering the Dillon 550 or 650, and happy to see it mentioned a couple times here.

I have so much to learn.
 
Ganderite said:
I have made small volumes of my best quality ammo using a single stage press.

I have made large volumes of quality match grade ammo using a Dillon 650 and a 550. They key was using ball powder, since it metered perfectly. For many purposes, this match quality ammo would be good enough. This was made with surplus Berdan primed military cases. Commercial cases might have produced a better result.

This is a test group fired at 520 yards from a rail gun.
Click to expand...

What ball powder are you having the best results with for 9mm and 45acp? Are you using the standard Dillon powder measure?
 
VanMan said:
What ball powder are you having the best results with for 9mm and 45acp? Are you using the standard Dillon powder measure?
Click to expand...

I load only 308 on my 650 with stnd Dillon thrower(with a case feeder). It uses an unknown ball powder similar to H335.

9mm and 45ACP loaded on a 550 with a standard thrower. I have excellent results with 7625, 231 and TiteGroup.

Standard accuracy loads with Titegroup:

9mm 135 gr cast lead 3.5gr

45ACP 200 gr lead SWC 4.3 gr
 
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