Does case length effect accuracy?

One thing I would caution....He shoots a Dasher in probably a 20lb+ gun. They are easy to shoot and super forgiving on the tune.

He shoots 7k+ rounds a year this is where his skill set pays the bills not the shortcuts at the loading bench.
Shortcuts on the reloading bench. I guess I must be in that camp then as some of his "shortcuts" I have been doing for 56 plus years. Nope I don't clean my primer pockets, nope I only trim when I'm over max case length, nope I don't polish my brass, nope I don't jack with case necks, I anneal after every firing (with a torch and a socket). Started reloading on a 30 Herrett, then a 357 Herrett, had to make my own cases out of virgin 30-30 cases. I've done 22-250, 7mm Mag, 6mm Rem, 300 Win Mag, 300 WSM, 40 SW, 45 ACP, 12, 20, 16 gauge and a few I'm forgetting. Single stage and progressive. That's my background. I try to read and analyze what folks say. Some have made sense, some have not.

YMMV
 
He shoots 7k+ rounds a year this is where his skill set pays the bills not the shortcuts at the loading bench.
This is how/why Cortina loads for world championship level F-Class on a Mark 7 autodrive progressive. He gets the processes done that he needs to and shoots a whole whole lot more.

But notice he also uses a Prometheus powder measure. Must be a benefit to non-digital measuring or else he wouldn't do it. Could be speed, precision, or both.
 
But notice he also uses a Prometheus powder measure. Must be a benefit to non-digital measuring or else he wouldn't do it. Could be speed, precision, or both.

Shortcuts on the reloading bench. I guess I must be in that camp then as some of his "shortcuts" I have been doing for 56 plus years. Nope I don't clean my primer pockets, nope I only trim when I'm over max case length, nope I don't polish my brass, nope I don't jack with case necks, I anneal after every firing (with a torch and a socket). Started reloading on a 30 Herrett, then a 357 Herrett, had to make my own cases out of virgin 30-30 cases. I've done 22-250, 7mm Mag, 6mm Rem, 300 Win Mag, 300 WSM, 40 SW, 45 ACP, 12, 20, 16 gauge and a few I'm forgetting. Single stage and progressive. That's my background. I try to read and analyze what folks say. Some have made sense, some have not.

YMMV

And if that works for you that's great.....My program is drastically different than yours and that works for me.
 
This is how/why Cortina loads for world championship level F-Class on a Mark 7 autodrive progressive. He gets the processes done that he needs to and shoots a whole whole lot more.

But notice he also uses a Prometheus powder measure. Must be a benefit to non-digital measuring or else he wouldn't do it. Could be speed, precision, or both.
Yeah, probably so. I use one of the original RCBS Chargemaster with a few tweaks. If I shot the 7K plus rounds, I'd invest in one, but I only shoot about 1K to 1.5K a year. Once again, what works for me probably won't work for anyone else.
 
But notice he also uses a Prometheus powder measure. Must be a benefit to non-digital measuring or else he wouldn't do it. Could be speed, precision, or both.

I shoot against EC all the time.

I also use a Promethous for the same reason he does......yes it can over throw and it can under throw by a kernel...but what it can't do is lie to you.
 
I shoot against EC all the time.

I also use a Promethous for the same reason he does......yes it can over throw and it can under throw by a kernel...but what it can't do is lie to you.
Greg Dykstra just did another video on loading, this time specifically on the Prometheus. I think I'm on the edge of going there. I've started shooting a lot more smaller cases where single-kernel variances is a higher % variation of charge weight, and compared to the guns and glass, travel, practice time, just everything that's consumed me over the last year the price tag is getting a lot easier to swallow if it makes the groups smaller and all the other time and money spent more worth it. Or even if it just results in more rounds fired and more practice that I feel better about.

If I had bought it first it probably would have been cheaper than everything else I tried along to way 🤣
 
If I had bought it first it probably would have been cheaper than everything else I tried along to way 🤣
This. Buy once cry once. Wish I could have but I didn't know about all the fancy stuff I just went to the store and loaded up the cart.
I recently had a buddy say he's getting into loading and want's to start with the best gear. I smiled and gave him a shopping list, he got a bit of sticker shock but I think he's over it now lol.

I can't justify a Prometheus for my uses. If I was shooting F-class maybe
 
Greg Dykstra just did another video on loading, this time specifically on the Prometheus. I think I'm on the edge of going there. I've started shooting a lot more smaller cases where single-kernel variances is a higher % variation of charge weight, and compared to the guns and glass, travel, practice time, just everything that's consumed me over the last year the price tag is getting a lot easier to swallow if it makes the groups smaller and all the other time and money spent more worth it.

If I had bought it first it probably would have been cheaper than everything else I tried along to way 🤣

I can't recommend it unless you are a high volume shooter.....or you just wanna own a super nice piece of gear.

I do know there is a powder charge thrower and scale that will be coming available within the year that is stupid fast and accurate.
 
I will say this, unless your brass length is beyond .040" longer than listed maximum length, you are no where near the chamber end of your barrel. Safety limits run between .030" (shortest) to .050" (longest) and the average across many chamber designs is .040".
If you believe this, look at chamber prints. I run my brass SAFELY at .010" shorter than chamber end, which is generally .030" longer than max case length, never had an issue doing this.
A chamber length gauge is a very useful tool…

Cheers.
P.S.
A brass neck often expands more on one side than the other, even if you neck turn…so, you MUST address this by moving the neck in ANY direction by the smallest amount possible. I aim for a maximum of .0015" and allow for .0005" spring back. That is both expanding and sizing the neck in total. My runout is barely readable.
 
I will say this, unless your brass length is beyond .040" longer than listed maximum length, you are no where near the chamber end of your barrel. Safety limits run between .030" (shortest) to .050" (longest) and the average across many chamber designs is .040".
If you believe this, look at chamber prints. I run my brass SAFELY at .010" shorter than chamber end, which is generally .030" longer than max case length, never had an issue doing this.
A chamber length gauge is a very useful tool…

Cheers.
P.S.
A brass neck often expands more on one side than the other, even if you neck turn…so, you MUST address this by moving the neck in ANY direction by the smallest amount possible. I aim for a maximum of .0015" and allow for .0005" spring back. That is both expanding and sizing the neck in total. My runout is barely readable.

It's my understanding that for mandrels to make effective, consistent change that they must move the brass a minimum of .002", which is just beyond the brass yield point. Presumably, even a fired, tight neck case would need to be reduced .005"-.006" and then increased .002" with a mandrel. A non-tight neck case would need much more.

How are you moving case necks a maximum of .0015"? I'm definitely missing something.
 
I am shooting a 300 Weatherby and my group size has increased about an 1" at 100yds and in checking found some of the cases as long as 2.84 most at 2.83, so I haven't checked them before each reloading just trimmed them after a few reloadings to 2.815. So now I'll check them before each reloading but was wondering if the longer cases would effect my group size?

I'm not certain if that would significantly effect groups on a typical weight "hunting" rifle!

Using my AI as an example…..I went to 10 firings on some cases without trimming or annealing, and there was no noticeable degradation in groups! memtb
 
It's my understanding that for mandrels to make effective, consistent change that they must move the brass a minimum of .002", which is just beyond the brass yield point. Presumably, even a fired, tight neck case would need to be reduced .005"-.006" and then increased .002" with a mandrel. A non-tight neck case would need much more.

How are you moving case necks a maximum of .0015"? I'm definitely missing something.
With honed neck dies, custom expander balls and mandrels, no neck movement, up or down, is moved more than .001", in which the case rebounds half a thou' as measured. I also do not believe a mandrel needs to move a case .002" to make it work consistently, this is far too much movement.

Cheers.
 
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