Maybe a weird question

DGY

DGY

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Good day all I was at the range with my new to me 257 AI shooting a ladder of nosler 115gn partition on top of some H4831sc!
Coal was 2.940, I had a node with shot 1and 2 but all 5 shots were inside 2”. Velocity wise I would like to be where shot 4 and 5 gave!
No signs of excessive pressure, primer rounded edges, easy bolt lift, easy extraction!
My question is, to achieve my desired velocity, should I seat my bullets deeper on the powder charge that gave me a node or load a few at 51gn and see how they shoot? IMG_2005.jpeg
 
DGY said:
My question is, to achieve my desired velocity, should I seat my bullets deeper on the powder charge that gave me a node or load a few at 51gn and see how they shoot?
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I don't think you told us what your loads were so I dunno if 51gr is close to shots 1-2, 4-5, or something else entirely.
 
Repeat the test and see what you got. One bullet striking beside another could be blind luck. Statistically irrelevant I believe is the term.

Edit. I should have looked harder at the velocities. If you want the speeds of shots 4 and 5, work around there. The velocity difference between 4 and 5 is actually closet than 1 and 2, indicating a plateau of sorts. HOWEVER again, as this is based off one shot, you might be in a place where SD and ES is trash and just lucked out. Smaller steps, up around the speed you want, looking for SD and ES rather than where the bullet hits.
 
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Hand Skills said:
How long is your barrel DGY ?

What is the diameter at the muzzle? I have found skinny barrels show a lot more dispersion on ladders than heavy barrels (or even medium contours for that matter)

100yd target I presume?
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100m target, barrel diameter at the muzzle is 0.660”. Barrel length is 24”
The rifle shoot sub moa( usually less than 3/4” with 75gn vmax and that is like every time I shot it)
 
There’s no way to be absolutely certain other than trial and error. But if I was tailoring the load I would:

-begin by seating slightly deeper. It can make a more repeatedly full load density without increasing pressure. In fact it will more likely decrease pressure.
-Failing that, I would use the .3gr increments as suggested above while still seating the bullets at a full load density, but still maintain some distance from the lands.

That’s just my process, in the goal of producing repeatable pressures and safe/moderate pressures. I never load anything hot, and I prefer accuracy over maximum velocity.
 
DGY said:
My question is, to achieve my desired velocity.......,
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small test there, but you may have a low node and may find another at a higher vel
3K is getting real close to max but you might be right there
whether it will be safe, or usable in diff temps, or tough on brass, well, more testing!
or you may have jumped a node already....

col is the last tweak imo
 
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I don't agree that doing initial ladder tests using load which are one grain apart is "too much"

One thing about doing it in one grain steps is that pressure shows up very fast and you know right away when it's too high. Then you can pull down the unfired rounds at and above the sweet spot.

The next thing is you find the "sweet spot" a bit faster, which then allows you to tweak that spot, without having to do a lot more shooting.

Looking at your pics, I wouldn't be "seatind the bullet deeper" but seating it further out, if the magwell allows it.

I don't shoot a lot of Nosler Partions these days, but from previous experience, have found they don't like "freebore" conditions.

I made a note in the records of the 257 Roberts and the 7x57, as well as the 280Remington rifles I shot them in, that they shot best when less than .010 inches off the leade (lands) and depending on the rifle they were being used in, even touching the leade.

From your pics, the load is very close to what your rifle will shoot well with your choice of bullet, but one critical piece of information you leave out is the twist rate of the rifling.

I have seen many rifles chambered for both the 257Roberts and the AI versions with 1-12 and more often 1-14 twist rates.

Often, they will not properly stabilize long-for-caliber bullets, such as the 115 grain Nosler, 25 caliber Partition.

The 1-12 twist rate works, if the loads are hot enough and often produce excellent accuracy. 1-9 twist is best for long, heavy bullets and 1-10 works as a great all-around twist.
 
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bearhunter said:
I don't agree that doing initial ladder tests using load which are one grain apart is "too much"

One thing about doing it in one grain steps is that pressure shows up very fast and you know right away when it's too high. Then you can pull down the unfired rounds at and above the sweet spot.

The next thing is you find the "sweet spot" a bit faster, which then allows you to tweak that spot, without having to do a lot more shooting.

Looking at your pics, I wouldn't be "seatind the bullet deeper" but seating it further out, if the magwell allows it.

I don't shoot a lot of Nosler Partions these days, but from previous experience, have found they don't like "freebore" conditions.

I made a note in the records of the 257 Roberts and the 7x57, as well as the 280Remington rifles I shot them in, that they shot best when less than .010 inches off the leade (lands) and depending on the rifle they were being used in, even touching the leade.

From your pics, the load is very close to what your rifle will shoot well with your choice of bullet, but one critical piece of information you leave out is the twist rate of the rifling.

I have seen many rifles chambered for both the 257Roberts and the AI versions with 1-12 and more often 1-14 twist rates.

Often, they will not properly stabilize long-for-caliber bullets, such as the 115 grain Nosler, 25 caliber Partition.

The 1-12 twist rate works, if the loads are hot enough and often produce excellent accuracy. 1-9 twist is best for long, heavy bullets and 1-10 works as a great all-around twist.
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That is exactly my approach! The barrel is supposed to be 1:12 twist!
 
Then, IMHO, that would indicate to me that I need to get the bullet ogives closer to the leade to get pressures up.

I've only got a few rifles, which have IMHO excessive freebore, which shoot well, and the dimensions in the chambers, including the diameters of the freebore portion are "tight"

The 257AI has a relatively "short" neck and again, IMHO, the base of the bullet needs to be controlled as much as possible before the ogive engages the leade.

As soon as expanding propellant gases start escaping around the bullet, control starts to falter.

I have a Palma Match reamer for 7.62 Nato, which I ordered with a "short/tight" throat so the ogive would be closer to the leade. The rifles I've used in all showed immediate improvement in accuracy. The only thing done to them was to set back the shoulder, shorten the tenon accordingly and recut the chamber enough to clean up the original chamber.

The one rifle I have left, with this chamber is a Remington 700, with a take off barrel, purchased at a gunshow for $50 with a 1-12 twist rate.

I built it to shoot the "surplus" ammo I have on hand, well enough to feel good about.

It has appx 1500 rounds through it now and it looks like I should take off the barrel and set it back another .035 inches to clean up the throat erosion, which always seems to be more prevalent with "surplus'' ammo.
 
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Ok, I made a mistake, could have been bad but it turned out it was a good one!
I don’t know what happened but a brain fart was the most likely reason!! So I loaded an other 3 rounds of what my heat thought to be 50.5gn of H4831sc, but in fact it was 55gn… I know really bad, but when I looked at the case the powder was just at the bottom part of the shoulder so still a ways from being compressed with my sheeting depth so I didn’t clue in. Anyway went back to the range shot those 3 shots and it produce the exact same average velocity, 3267fps, all 3 shots went where yesterday’s shot were(used the same target) but a smaller group of 1/2”@100m, the primers are some what flatish but still have some radius on the edges, not problems with bolt lift with so ever… what would you do?
The rifle seem to have lots of free bore…

IMG_2027.jpegIMG_2028.jpegIMG_2029.jpeg
 
If you're happy with the velocity/accuracy, leave it alone and load up a bunch more.

That primer is fine as long as it isn't backing out and you're getting propellant fouling below the shoulder.

It appears that you could even add a grain or two to the load, which I would do just to make sure.

The 257AI I had loved the loads right at the top end, very close to maximum. I did load some beyond the max loads to see if there was an advantage, but once that point was reached, nothing changed, other than the primers flattened more and cratered.

The 257AI likes to be loaded HOT from my experience and it thrives on H4831 as well as W760.
 
Thanks bear hunter, I’m definitely happy with velocity with those nosler partion and also accuracy at under 1/2” lol
 
bearhunter said:
If you're happy with the velocity/accuracy, leave it alone and load up a bunch more.

That primer is fine as long as it isn't backing out and you're getting propellant fouling below the shoulder.

It appears that you could even add a grain or two to the load, which I would do just to make sure.

The 257AI I had loved the loads right at the top end, very close to maximum. I did load some beyond the max loads to see if there was an advantage, but once that point was reached, nothing changed, other than the primers flattened more and cratered.

The 257AI likes to be loaded HOT from my experience and it thrives on H4831 as well as W760.
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I here is what the bullet would look like seated to be about .050 from “jam”/land”
That bullet in the land the coal would be 3.1185, seated at 3.0685 it still fits in the magazine and still have .257” of the bullet inside the neck!
What will I gaine by going from 2.940 to 3.0685 coal?
 
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