|
|
Post by ET on Jan 28, 2020 16:01:30 GMT -5
My personal belief is that there are still some areas to explore to see if better results can be obtained.
Okay some might think why I’m delving in a past era with the 50 and sabots when 45 Cal or even 40 is now more the norm? That would be like asking a driver why he enjoys driving much older cars. The answer is simple, that’s where I want to be. Maybe one day I might get a barrel replacement of another Caliber for my 10ML-II but for now I have a lot of unfinished testing to do with the 50.
When my testing gets going in the Spring again and hotter summer conditions move in, I won’t be putting my SML aside until cooler weather arrives. I suspect the hotter temps make the sabots more pliable reducing bore fit tightness. Here I plan to regain that tightness with increased knurling to see what happens.
Today I don’t look at a sabot like I once did of just simply holding the bullet while in the bore. Let’s just say there’s more than what meets the eye.
And I feel there’s a lot more to discover with future testing especially with powders. The hard part now is waiting for the right weather conditions to start again.
My personal goal for 2020 is to assemble some of what I believe are accurate model loads for different bullets. For me satisfaction comes when I have a dependable and accurate load so all that’s left is shot placement. Okay there is some messy work to follow afterwards, chuckle.
Ed
|
|
|
|
Post by reloader22 on Jan 28, 2020 18:41:33 GMT -5
As you test, please try something: I have not seen sabot failure or temp sensitivity using H4198 in my 50 during warm weather yet using 4759 and N110 it's almost guaranteed. Been using this powder for many years and have not had sabot issues. Harv CR and .458 bullets. 300 gr at 70 gr of powder and Barnes 250 TMZ using the supplied sabots and up to 80 gr H4198 at 2,800 fps. I load and shoot with little time waiting. Back in the day I would have all kinds of sabot failures with book powders at upper levels. The slower powders seem more forgiving. Maybe my barrel is different.  ?? Here in the cold ML season, H4198 has never failed to go bang but I have heard of others who say otherwise. Hmmmmmm |
|
|
|
Post by ET on Jan 28, 2020 22:31:59 GMT -5
Reloader22
First thanks for sharing that info from your experience. I have H4198 on order from Bass Pro to try with 275XPB for developing a potential moose load. Boy if I get that to 2700fps I’d be one happy camper.
As for having sabot failure with book powder loads, which I’ve haven’t experienced but then again when it gets hot out, I haven’t shot with sabots. That’s going to change this year.
As for sabot failure I have a theory as to why. The plastic becomes more pliable (softer) when temps increase. This should loosen the sabot fit to bore possibly allowing the on rushing hot gases to find a weak spot to work past the sabot skirt causing failure. Or if the load is too loose the bullet may punch the sabot. This would more readily happen with a load with a faster Rise Time (pressure build up).
Previously I thought the bullet supported the sabot base for containing pressure. Now if the bullet has any movement because of a looser fit then what support does it add to the sabot base? So now if we add a tighter bore fit preventing bullet movement, we strengthen the support for the sabot base.
One other option left that SW recommended is using a wad to add some shielding from the on rushing hot pressurized gas.
I will definitely be monitoring and comparing Rise Time of all the different powder loads and any abnormalities.
I don’t believe your barrel is different or has any issues with the way it is handling the 4198 loads. If others are experiencing 4198 ignition problems then they may want to consider tightening their loads and use powder compression when loading IMO.
Ed
|
|
|
|
Post by sw on Feb 18, 2020 22:03:08 GMT -5
Concerning sabot integrity, light knurling and possibly a vege wad in lieu of a wool wad may help. I think the vege wad may be more protective.
|
|
|
|
Post by ET on Feb 19, 2020 9:26:18 GMT -5
Concerning sabot integrity, light knurling and possibly a vege wad in lieu of a wool wad may help. I think the vege wad may be more protective. Thanks for the recommendation of wad choice. I only have wool wads at the moment to try if needed. What I really need is an early Spring arrival with temps warm enough to take my laptop outdoors again. Then I can start collecting necessary data I'm looking for. Eventually I want to tabulate all the info into a guide line for each load and conditions. This should keep me busy for a while, chuckle. Ed |
|
|
|
Post by sw on Feb 19, 2020 11:17:21 GMT -5
Agree. Without question, a wad underneath a sabot will allow a higher pressure load.
|
|
|
|
Post by ET on Feb 19, 2020 13:20:01 GMT -5
Agree. Without question, a wad underneath a sabot will allow a higher pressure load. SW I've never had a blown sabot and I plan to keep my loads under 40K. From your experience would you have an idea at what peak pressure would be detrimental to sabots. I have both Harvester and MMP sabots for this testing phase. I know the 10ML-II barrel can handle 50K PEAK PRESSURE but I would prefer to err on the side of caution. Ed |
|
|
|
Post by sw on Feb 19, 2020 22:42:29 GMT -5
Ed,
The majority of my testing was conducted back around 2000-2001 with 100s of shots a day. Sabots were not as tough back then. Additionally, I didn’t knurl any back then. Likely, a wad will not be any advantage for your loads. Probably, in a cool barrel, lightly knurled bullets, and modern sabots, even 50K would not blow a sabot. I feel like the wad is an insurance policy . I’ll admit, I’m a creature of habit.
|
|
|
|
Post by ET on Feb 20, 2020 17:18:37 GMT -5
SW
Back in the day when SML first appeared You and others lead the pioneering of load development and other improvements. This helped me to get my 10ML-II to start performing what I needed for hunting. As I continued to follow this Board more improvements developed but for a while, I was reluctant to go further. Losing 4759 was the nudge I needed to get into gear again and advance my load knowledge with my SML. Over the years I have collected enough equipment to allow me to do my own exploration for load improvement.
I do have at least one test planned using a wad. When heat arrives in the summer time I know that loads will loosen some. Without adjusting load tightness, I want to see what benefit a wad would have in this situation. Like the old saying goes, change one variable at a time and observe results.
Ed
|
|
?? 