cohunt
Well-Known Member
next time record where each shot hits the paper target also--- youll often find nodes that way as well
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Very strange ladder tests
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six pack
Well-Known Member
Used Hodgdon data but also looked at Nosler. Stopped below max due to capacity of Lapua brass.
Agreed. I find it easier to see nodes from the impacts on paper rather then just the velocity.
I'm with Tdot. I find my nodes on paper as opposed to the Chrono. Then chrono after for starting dope info
Just checked... Nosler data is max of 46.0 of IMR4350 at 2840fps, that's with a 2.800" COAL.
I've never personally seen a huge difference in the admittedly limited comparison tests that I've done between H4350 and IMR4350 (and that was in a 308).
A couple questions.
Have you reloaded for a Kimber before? My Kimber 308 shows pressure signs very differently then my other rifles. I dont know if it's a function of the rough bolt face milling or the CRF ejection... maybe its just me.
What's your COAL?
I've never personally seen a huge difference in the admittedly limited comparison tests that I've done between H4350 and IMR4350 (and that was in a 308).
A couple questions.
Have you reloaded for a Kimber before? My Kimber 308 shows pressure signs very differently then my other rifles. I dont know if it's a function of the rough bolt face milling or the CRF ejection... maybe its just me.
What's your COAL?
six pack
Well-Known Member
This is the only Kimber I've ever loaded for. Don't have a COAL as I loaded .03 off with a Hornady comparator.
Prairie Dog Assasin
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If this powder doesn't work as well as you would like, try Re-19. We have shot all but 2 deer DRT and one of those went 30 yds. 140 Partition, Re-19, Fed brass + primer. Gun is Rem Model 7 20" SS.
catamountsierra
Well-Known Member
I plotted up your data because I find it easier to see what may be going on that way. I would stick to the 46.0 to 46.4 range if it was me. Higher than that and the variability starts to go way up. I used to run a Remington 700 in 7mm-08 shooting the 140gr Accubond over about 46.3gr of H4350 (I'd have to look it up to be sure, but it was in that range). That was giving me around 2815fps out of the 24" barrel and was about the max before I started seeing pressure signs. The increased variability between the two strings above 46.4 worries me and, my guess, would end up showing increased SD and ES when shooting groups.
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cohunt
Well-Known Member
that graph does help-- shows a possible node at 46.4 and maybe 47.4--try both and see--use a target this time too
Just throwing this out there. But I'd be very cautious with this load. The variability between the two loads is cause for hesitation but not overly concerning to me, definitely worthy of further investigation. But the fact that they both start to decrease at the same time would suggest to me that it is over pressure. I've personally never seen or heard of a decreasing velocity spread that is a good thing. I'd personally stay a minimum of 1 grain below that point.
Has anyone else seen increasing powder charges and decreasing velocity and had good results?
Has anyone else seen increasing powder charges and decreasing velocity and had good results?
lancetkenyon
Well-Known Member
Without a target to show POI for each shot, I don't take speeds alone into much account. You could easily have a 50-70fps difference between 4 charge weights that has very little vertical dispersion, which is a very forgiving node.
Shoot at 400, and record that info, then revisit the topic.
Shoot at 400, and record that info, then revisit the topic.
BallisticsGuy
Well-Known Member
Based on my look at your initial set of numbers, it looks to me like 47.4 and 45.8 look to have produced the most stable results.
Canhunter35
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Repeat what you did on paper at 400yds or Farther without the magneto speed strapped to the barrel. A node will group together. Also .3gr is close enough for a 7-08
7mmTikkaShooter
Well-Known Member
Oofta! These are some muddy waters kind of results. Frustrating I'm sure. Several things come to mind here:
1) chronograph error. Could the Magneto Speed have been or wiggled a little loose or just setup too close or far from the bore?
2) Bearing surface variations. Did you sort bullets for this?
3) Seating depth. In my experiences with Nosler ABLR's they're known to be pretty soft and like a bit more jump. Loaded too close and you may see inconsistencies. I've been told that the Partition construction is similar to the ABLR so is it possible that 0.030" jump is too close?
4) Primers. Could a switch here show more consistent ignition?
5) Powder. It's possible that this combination of brass, bullet, powder, primer, and gun just don't work as expected. Though all are high quality components, they just might not be the best recipe. Switching to a faster or slower powder might make ignition more consistent.
6) Neck tension. This can be critical in consistent velocity. Lapua brass is known for its consistency but have or can you check it?
Looks to me like it's worth testing again. I'd start by sorting bullets by bearing surface, then checking the neck tension and possibly turn them if you thought it was a factor, then check seating depth at the ogive. When it's time to shoot I'd be triple sure the magneto speed is setup perfectly. I would also load 3 per charge and use the average velocity as that's the basic minimum for scientific data. If your results are erratic again after that test it would seem time to swap primer and/or powder components. I wish I could give you a more expedient or economical answer but this data is just too erratic to glean any info from in my opinion. Check your component consistencies and give it another go. Good luck and keep us all posted. Here's hoping we can all learn something.
