Reloading question on seating depth

[Acm]

Hi all, recently made a rookie error reloading despite being at it over 10 years now!
Developed a great load for my 06 using Barnes 175lrx and superformance powder. Fantastic expansion, good accuracy (around an inch, just under if I do my bit) and no pressure signs. BUT, I top loaded the rifle during load development and found after loading 100 rounds that they were seated ever so slightly too far out to work in my Mauser’s magazine flawlessly. Today I seated 3 bullets 20 thou deeper, and went to check them on the range and to my surprise they shot a good inch higher at 100m.
Still no pressure signs, still good accuracy, but seemed to be going a fair bit faster.
Can anyone explain this? It seems a tiny change in seating depth to have such a notable effect.

 

[User00040]

Hi all, recently made a rookie error reloading despite being at it over 10 years now!
Developed a great load for my 06 using Barnes 175lrx and superformance powder. Fantastic expansion, good accuracy (around an inch, just under if I do my bit) and no pressure signs. BUT, I top loaded the rifle during load development and found after loading 100 rounds that they were seated ever so slightly too far out to work in my Mauser’s magazine flawlessly. Today I seated 3 bullets 20 thou deeper, and went to check them on the range and to my surprise they shot a good inch higher at 100m.
Still no pressure signs, still good accuracy, but seemed to be going a fair bit faster.
Can anyone explain this? It seems a tiny change in seating depth to have such a notable effect.

Did you actually chrono the load or are you assuming an increase in velocity?

Superformance tends to work better under slight to moderate compression.

 

[ashray]

you have increase the pressure= velocity by reducing the amount of space for the powder to burn, a reloading manual will explain it better than i can .if you use these 3 loaded rounds on a hot day you MAY get unwelcome results.

 

[jcampbellsmith]

Hi all, recently made a rookie error reloading despite being at it over 10 years now!
Developed a great load for my 06 using Barnes 175lrx and superformance powder. Fantastic expansion, good accuracy (around an inch, just under if I do my bit) and no pressure signs. BUT, I top loaded the rifle during load development and found after loading 100 rounds that they were seated ever so slightly too far out to work in my Mauser’s magazine flawlessly. Today I seated 3 bullets 20 thou deeper, and went to check them on the range and to my surprise they shot a good inch higher at 100m.
Still no pressure signs, still good accuracy, but seemed to be going a fair bit faster.
Can anyone explain this? It seems a tiny change in seating depth to have such a notable effect.

Did you also shoot some of the original unaltered rounds for reference?
Regards
JCS

 

[Lancaster]

You need to chrono the original and deeper seated loads to see if there is a difference, I suspect that you will find a modest increase in velocity.

The POI change may be down to the bullet taking a slightly longer time to exit the muzzle due to it taking more time to exit the case mouth, or a slightly shorter time due to the increase in velocity, so it will be exiting the muzzle at a different point in the barrels oscillation hence the difference in POI.

 

[Smellydog]

Don't worry about it.

 

[Namman]

Hi all, recently made a rookie error reloading despite being at it over 10 years now!
Developed a great load for my 06 using Barnes 175lrx and superformance powder. Fantastic expansion, good accuracy (around an inch, just under if I do my bit) and no pressure signs. BUT, I top loaded the rifle during load development and found after loading 100 rounds that they were seated ever so slightly too far out to work in my Mauser’s magazine flawlessly. Today I seated 3 bullets 20 thou deeper, and went to check them on the range and to my surprise they shot a good inch higher at 100m.
Still no pressure signs, still good accuracy, but seemed to be going a fair bit faster.
Can anyone explain this? It seems a tiny change in seating depth to have such a notable effect.

Try them again, could be pilot error or different atmospheric conditions !!

 

[Acm]

Did you also shoot some of the original unaltered rounds for reference?
Regards
JCS

Yes they shoot to the same point of impact, but about an inch and a bit lower.

 

[Acm]

Don't worry about it.

Not at all worried about, just like to further my knowledge.

 

[Acm]

Did you actually chrono the load or are you assuming an increase in velocity?

Superformance tends to work better under slight to moderate compression.

I haven’t chrono’ed the adjusted bullets. But I did the original load. 2780fps, I love superformance powder!

 

[User00040]

I haven’t chrono’ed the adjusted bullets. But I did the original load. 2780fps, I love superformance powder!

Good powder which was 'undiscovered' for a while but new prices are through the roof!

 

[nowler]

Seating depth changes will alter where the group prints on the target.

 

[Smellydog]

I haven’t chrono’ed the adjusted bullets. But I did the original load. 2780fps, I love superformance powder!

With respect...I don't get what's so special of superformance powder, that's the kind of velocity good old h4350 would give

 

[Acm]

With respect...I don't get what's so special of superformance powder, that's the kind of velocity good old h4350 would give

According to Barnes, Hornady and Nosler data it’s atleast 100fps faster at the muzzle with superformance than h4350. In actual fact the only powder that comes close, and it doesn’t match it, is a compressed load of reloader 22. The problem with that is that with a long heavy mono like the Barnes LRX you can’t get the bullet in the case on top of 62 grains of anything. Hence why I sold 4 lbs of reloader 22 after trying.
But of course what’s really special about superformance is when I went into dauntsey guns they had 14lb on the shelf. I only wish they had half as much h4350, I had a phenomenal load with that in my 6.5x55 under 140grn sst’s

 

[Tis1979]

As said I would use a chrono to see what there running at but also personally I would be looking better than an inch at 100m with home loads. if there only just fitting in the mag now then I would experiment with seating them deeper (obviously watching for pressure signs) and keep an eye on your group size as it may well improve.

 

[Stalker62]

... an inch at 100m...

 

[deerstalker.308]

Got to love this surely!??

 

[Acm]

It’ll shoot under an inch with Berger target bullets but with hunting ammo, I tend to zero at 200m and these group just over an inch. Well within Minute of Deer

 

[JTO]

you have increase the pressure= velocity by reducing the amount of space for the powder to burn, a reloading manual will explain it better than i can .if you use these 3 loaded rounds on a hot day you MAY get unwelcome results.

I have always thought that the change in performance due to adjusting the seating depth has more to do with the change in the case percentage fill than the difference in time that the bullet takes to get out of the case neck, perhaps.

 

[Tis1979]

Apologies, I didn't realise the group was at 200m. hope you work it out