Noe k31

[zomby woof]

Finally got around to shooting my K31 with my new boolits. My load was 32.0 4064 with filler .310" GC 2500 lube. All shots stayed in the 10 ring at 200 on the SR target. Nice boolit!!!

[legend]

Well done,nice shooting!

[Danderdude]

Just got the K31 mold from a new production run. I'd love to see more loadings from others.
Thus far I've only been shooting at steel targets but I'll put some on paper soon.

Rifle: 1947 K31
Sights: Factory notch and post, at 100m (minimum) setting.
Stance: Supported Standing (leaning against pickup bed)

Brass: Prvi Partizan 7.5x55
GC: Hornady
Lube: White Label BAC
Sized: .309
Alloy: Water-dropped Hardball
Primer: CCI 250 (Large Rifle Magnum)

Load: 20.5gr 2400
Estimated Velocity: 1850 FPS
Very little recoil, as expected. Hit 11/12 on 8" diameter steel at 150 yards. Shows promise.

Load: 32gr H4895
Estimated Velocity: 2250 FPS
Moderate recoil. The difference in speed in clear, and the sonic crack much louder as we break Mach 2. Hit 24/24 on 8" steel at 150 yards. Had one case failure: burn-though at the shoulder/neck junction. No overpressure signs. Will work this load to an estimated 2500 FPS in the future.

Paper, longer shots and other photos will follow in the next week.

[IllinoisCoyoteHunter]

I haven't got my mold out of the box yet but will be following this thread with interest...

[hicard]

I am using mine for the 300 Blackout and it is working great. No feeding/chambering/firing problems at all. Just what I wanted it for. Still have to take it to the range for target work but I feel it will do great.

[Danderdude]

Rifle: 1947 K31
Sights: Factory notch and post, at 100m (minimum) setting.
Stance: Supported Standing (leaning against pickup bed)

Brass: Prvi Partizan 7.5x55
GC: Hornady
Lube: White Label BAC
Sized: .309
Alloy: Water-dropped Hardball
Primer: CCI 250 (Large Rifle Magnum)

Weather: 50F, 20mph perpendicular cross wind
Target: 8in diameter steel plate @ 150 yards

I decided to try some near-max loads today. The wind was at a pretty good clip and highly variable though, so I did not bother putting out paper. The overall goal is to develop a cast-lead GP11 analog that can use the original sights out to 400 yards.

Reference Load: 32gr H4895
Estimated Velocity: 2250 FPS
6/6 on 8" steel plate @ 150 yards. Still works.

Load: 14.5gr Unique
Estimated Velocity: 1600 FPS
Low-moderate recoil. First 3 hit low with rear sight on 100m settings. Moved sight leaf to 200m setting. 2/3 struck target.

Load: 22.5gr 2400
Estimated Velocity: 2000 FPS
Moderate recoil. 1/6 hit target. Will have to try to pattern on paper when wind dies down.

Load: 35gr H4895
Estimated Velocity: 2350 FPS
High (relatively) recoil. 1/6 on steel. Looks like they were hitting all around it. No leading.

Load: 39gr H4895 WARNING: OVERPRESSURE SIGNS WITNESSED, PROCEED WITH EXTREME CAUTION AND WORK UP SLOWLY
Estimated velocity: 2450 FPS
3/6 cases showed slightly flattened primers. Accuracy inconclusive. No other overpressure signs seen.

I've been going by the .308 Win. data in the Lyman cast handbook, and while 40.8gr is the listed max load for their 187gr spitzer, I can not recommend any more than 35gr for now.

I'll shoot paper when it dries up enough to walk through the pasture and wind dies down.

[excess650]

DD,
Try H322 in your K31. Start several grains lower, but mine shoots 30gr H322 F210 primers Lyman 311644 (200gr) very well. You might be well advised to start around 25 grains and work UP looking for accuracy and then accuracy disappearing. I went as high as 35gr. 34gr shot good groups (sub 2moa) but 35gr was pathetic. 30gr shot better, and 29 and 31 still shot well.

The PP 7.55x55 cases have the same capacity to the bottom of the neck as do RP 30-06 cases. The twist of the K31 (1-10.65"?) is more like the 1-10 30-06 than the 1-12 normal twist of the 308. The cartridge should be more akin to the 30-06.

[giz189]

I used 20 or 21 grains in my first loadings. Don't remember the group I shot with it, but it works great on armadilloes 0 to 50 yds. Of 2400 powder.

[madsenshooter]

The only shots I've taken with this bullet were loaded over 44.4gr of H4350. 3 of 4 were touching at 100yds, and the 4th less than an inch out. The nose casts a bit large for my K31, which is tighter than the norm even, and I have to seat below the neck/shoulder junction. But that didn't appear to hinder the accuracy any.

[Danderdude]

Dutch,

Since I haven't been loading long, I choose to err on the side of caution by using load data with a heavier bullet and smaller case capacity. It boggled me why I was seeing flattened primers, but the twist likely does have something to do with it. I'm leery to reference .30-06 just yet.

The Lyman .308 Win 187gr load data stops at H4895 and doesn't encompass anything slower.

Mind yall, these were some impromptu tests, standing, on a windy day, at 150 yards, off irons set for 100. The accuracy may be good. I'll just have to wait for the right time.

As far as obturation, by the reference materials I've got, I should be right at the sweet spot loading between 40k and 45k PSI. "Should", being the operative word.

excess,

I appreciate it, but my goal right now is to first find a 2500fps load, and then a reduced load that will hit closer targets by simply adjusting the leaf sight, i.e. a 100 yard load with the sights set at 200.

madsenshooter,

If I can't get H4895 to work on a good day, 4350 or RL17 will be my next stop.

[madsenshooter]

Obturation is not something you really want. I used to think so too, after reading some on the LASC site. Wouldn't be needed in a bore as tight as the K31's. In revolvers, where the bullet is sometimes sized down by the cylinder or forcing cone, and needs to bump back up to fill the bore, yes, in a rifle, no. (One exception being a rifle bore that has a reverse taper.) You're just deforming the base of the bullet and getting up into pressure levels you don't need or want with cast bullets, pressures maybe high enough to make the bullet slip in the rifling some. Richard Lee has a whole section on pressures with cast bullets and why slower powders are better in his book Modern Reloading. The big point is, you develop the pressures slower with the slower burning powder, so your alloy is less likely to be, as Dutch put it, overstressed, as you look for that higher velocity. Slower is better, with slow powders like 4350 I can maintain accuracy in my 6x45 up to 2450fps. With pistol type powders, 1600fps. With relatively fast rifle powders, such as 4198, 2100fps. 4895, around 2250fps. These are all with the same bullet cast of the same alloy. Sometimes you'll run across posts by Larry Gibson where he refers to the RPM threshold. Not a set figure, or limit, it's Larry's terminology for the same overstressing mentioned above. I really didn't know what he was talking about until I developed the loads for my 1/8 twist 6x45 starting from pistol powders and progressing up the burn rate chart. Dutch is right, for the top velocity while maintaining good accuracy, you'll probably wind up using powders slow as he's recommended in order to get to 2500fps without shooting shotgun pattern groups.

[Danderdude]

I promised benchrest paper and here it is.

Rifle: 1947 K31
Sights: Factory notch and post, at 100m (minimum) setting.
Stance: Marginally stable bench, sitting

Brass: Prvi Partizan 7.5x55
GC: Hornady
Lube: White Label BAC
Sized: .309
Alloy: Water-dropped Hardball
Primer: CCI 250 (Large Rifle Magnum)

60 degrees and a 10 mph steady wind perpendicular to the flight path.

1 serious issue: everything is shooting high, even with sights set at 100m. I'll need a shorter front sight.
I loaded:
6 35gr H4895
7 36.5gr H4895
6 38gr H4895

Instead of loading enough of the 35gr for calibration and sighting in, I shot them all before checking the target. Way high and left. This is a 6 shot group. Two shared an oblong hole on the left. One hit between the papers.


While trying to align the front sight I shot a pair of strings of 21gr 2400 and aimed low...
eww....


Here are the 7 36.5gr H4895 loads (I found a lost piece of primed brass and tossed it in for ****s and giggles. The 38gr loads that hit the wood are all around it.


I can't believe how much trouble I was having getting the front sight aligned.


Looks like yall are right, I'll need a slower powder for higher velocity.

Anyone want to offer an explanation for why I'm shooting 3-4 inches high? They do make some pretty hard to find replacement front post inserts. I'll have to track down a taller one.

[madsenshooter]

Wow, those are some biiiig pics. Nice ones though. Yea, you're seeing the same thing I was as I was working up through progressively slower burning powders. But that's good because it means you might be able to make use of that cheap slow burning stuff Wideners sells for $39/8lb. It would probably need a little charge of fast burning powder under it to get the velocity you're looking for. I use 3-5gr of Blue Dot. The powder is designed to be ignited with a primer a lot more powerful than any large rifle primer and when it gets that mo powr it burns like 4350 or 4831. Dutch the difference between a standard 7.5x55 case and one that's been blow out in a K31 chamber amounts to about 6gr more powder capacity, IIRC.

[1johnlb]

Anyone else have any good loads for NOE's 180 fn k31. I started with 4064 with horrorible results then went to 4227 and dacron, and had alittle luck right around the 17-17.5 gr range. I'm going to 4831 next after reading this thread.

Just tring to crank this thread up to see what ya'll have had success with. PLEASE SHARE!