PR Bullet duplex sabot

[Big Jack]

Has anyone played with these?

Savage 10 ML-II and I use smokeless so experience with this specific setup would be helpful.

I will be throwing 200 grain bullets and I am thinking I may have to go higher than normal charge wise to get good stabilization.

[MikePal]

I read about the 'duplex' sabots many years ago and was confused so passed up on the idea of giving them a try. Your thread got me to go back and reread about them again this morning and am still a little confused as to the 'why' reasoning behind it all.

I have shot the .40/.50 dead centers, in fact still have 3 packages sitting here. I know the .40/.50 dead centres are deadly accurate out to 150 yds, I trialed them a few year back and was super impressed. The idea that the .357 bullet is that much better than a .40, to the point of having to develop the special 'duplex' sabot system to shoot them still has me scratching my head. But Cecil swears by it and his performance results show them to work.

Have to let me know what you find. I don't shot MLs out to the distance that these are designed for (200+) so I have little interest in spending the time and money to trial them myself.

[ET1]

Big Jack

Best of luck with your new project of duplexing sabots.

I tried my own mixture of sabots to get the 200SST .400” to fly but when I exceeded 2000fps they sprayed like wild fire.
For single sabot load using 200gr bullet I tried 460S&W 200XPB (.451). Here to I started to get wild groups after a certain velocity.
Never tried PR’s setup so I can’t say how they work.

Your 10ML-II has a 1-24 twist so higher velocity than 2000fps shouldn’t be required for sufficient gyroscopic stabilization (RPM) for say the 200SST.
Another bullet I haven’t worked with is the 200FTX .452”.
http://www.hornady.com/store/searchammo.php?mode=search&main_cat=250&categoryid[]=260&categoryid[]=429&categoryid[]=&x=42&y=5
I do know the 225FTX shoots as good as the 250FTX.

A possible problem with lighter copper clad or copper bullets may be insufficient obturation. This may not be so with all lead bullets.
Definitely let us know how you make out.


Ed

[Big Jack]

I run the 260 gn dead centres with excellent results to 200 yard. Velocity is about 2300 fps Mark. Reasonably heavy recoil. Going with a 200 grain pill with better bc I think I will have to up my charge simply because it should yield higher velocity and stay within safe pressure. Higher velocity is the goal with increased range.

Problem I see is with the powder I typically use being sr4759. It is relatively quick so I think I will need to look at some of the other suitable powders I have.

I use 4759 in reduced recoil loads for many Cals and it tends to produce close to maximum pressures but of course lower velocities. There may be a better powder out there for lighter pills in this ML.

[ET1]

Big Jack

Not sure where your reasoning is originating from for lighter bullets that normally have a lower BC. In order to produce the same drop at a given distance you need higher velocity with a lighter bullet.

For the responsiveness of 4759 there is a big difference from the old 1/2lb can and the now 1lb plastic container. For the standard recommended 4759 load for the 10ml-II there is about 5k/psi difference in pressure and about 100fps difference for a 250gr bullet.

Anyway enough said for now and will look forward to hearing about your results when you put your testing in gear. My main curiosity will be your choice of powder and how responsive it is to temperature change with a lighter bullet.

For what it’s worth a load of 55gr - 4759 (1lb container) and 200grain bullet generated around 30k/psi with a resulting velocity of around 2450fps.


Ed

[Big Jack]

Thanks Ed.

My thinking is this;

In rifle reloading as your bullet weight goes down, your charge weight increases which brings you back to max pressure again. Often powder type may have to change as well. I know it isn't the same thing as you are not forcing a metal bullet up through riffling but hopefully you can see my thinking.

Greater velocity coupled with a bullet that flies better should give you greater range and better trajectory.

These 10ml's have load data set for 4759 at 43 grains and that combo works well with a 260 to 330 grain bullet. The original 10 Ml's were designed using 300 grain bullets. In my mind when you drop bullet weight down by such a huge amount, 4759 may no longer be the right powder.

Did iyou see incomplete powder burn with the 200 grain set up?

Was pressure comparable to one of your 260 or 300 grain loads?

This just may be a wild goose chase. Temperature stability is definitely a concern.

[Big Jack]

Here are some powders I am looking at. I have used 5744 with ok results.
H4227 is n extreme powder so temp sensitivity should be ok and I have that one.

AR2205 (ADI)
4227 (IMR)
H4227 (Hodgdon)
5744 XMR (Accurate)
N130 (Vihtavuori)
680 (Winchester)

Has anyone played with these?

[ET1]

Big Jack

Load experimenting is never a wild goose chase but a learning experience for me.
Okay I see your reasoning just not how you define max pressure.
To answer your second question I saw no evidence of an incomplete burn using 4759 with a 200gr bullet.
Here’s an experiment you may want to try to compare lighter bullet to a heavier bullet.
Same zero (height) at 100yds for 200gr and 250gr bullet. Without further adjusting anything move to 200yds and see where the POI is for both bullets.

Sorry I don’t use 300gr bullets as I never saw a need to with what the 250gr provided.
I did do a test for another individual using a 325gr bullet with 4198 that registered 38K/psi. Now that would have rattled my back teeth if I wasn’t wearing a shoulder pad, chuckle.


IMO 4759 is a tad slow but usable with a 200gr bullet. At 1-time Alliant 2400 was a recommended powder that used less grains per recommended 250-loads. This will be a powder I eventually want to try with 200gr bullets.

Ed

[Big Jack]

I see your point with regard to max pressure.

2400 is something I will order. I also have 5744 which I have had some success with.

Thanks Ed

[MikePal]

I don't know if you guys have seen the load/pressure tables included in this article by Randy Wakeman for the 10ML...some interesting info;

http://www.chuckhawks.com/savage_accuracy_loads.htm