will someone tell me how duplex loads are unsafe

[cummins cowboy]

after looking at the smokeless alternative forum that is now closed here it looks like this forum wants to stay with traditional loads, thats ok its a choice,

I guess what I am looking for is all the info I can about how safe or unsafe a duplex load may or may not be. I have read some interesting info in the past few days, as a result I don't believe all I read just because someone wrote it. I wanna learn for myself. so does anyone have any evidence of duplex loading causing safety issues??

do you guys hunt with these loads?? if so what is the best way to, keep your loads ready for a quick reload??

 

[redpep]

Head over to Doug's green board.
savage muzzle loading, there's a lot of reading on duplexing

 

[cummins cowboy]

I have been over there, I would like to bring some more discussion over here, smokeless ML seems like a way to make MLing exciting, plus much more hassel free, anyone have an idea on how much the extra 2" on the savage ML BP will add speed wise

 

[big6x6]

I've never shot a duplex load so I've certainly never hunted with one.. I'm willing to make do with a 200-225yd limit on shots so loads using SR-4759 and N-110 do just fine for me... Also I'm not so crazy about the added recoil either....

 

[AJ]

Duplexing [when done properly] can definately allow the shooter a lot more variety in their loads. It's not that far off of using a flintlock when you have 4f in the pan and 2f in the bore. People jumping into this should have a decent knowledge of internal ballistics and good common sence as you are treading into uncharted territory.

I have used a few duplex loads in my Savage. It allows you to go from mild to wild, your shoulder is usually the limit. When I hunt with them, I was using empty rifle cartridges to hold the powder. I had a 30-06 Improved case for the main charge and a 221 Fireball case with the ignition charge. These were taped together for a single load. I used foam earplugs in the neck to keep the powder in. If I was going to hunt Canada with my Savage, I would travel with my loads built like centerfire ammo and pull bullets when I arrived at the hunting destination with a pair of pliers.

 

[neonmoon]

unsafe???

If the questions is......why use duplex?.... there is a detailed answer for that. But the short answer is that there is no single powder that is perfect for shooting 250 grain bullets to increased speeds from a 50 caliber bore. H-4198, Reloder7 and maybe N120 come close but if you want to shoot really fast, duplexing can help without increasing pressures to unsafe levels.

If the question is......is duplexing safe?.....the answer is that it undoubtedly is safe. All you are doing is using a faster burning powder to help with ignition and pressure so that a slower burning powder can get going and do it's job with such a light in weight projectile. The benefits are increased speeds and usually better accuracy. Recoil will depend on how much of the secondary powder to be used and that is controlled by you.

For those who want to reach speeds of 2200-2300 fps with 250 grain bullets can use 43-46 grains of SR4759 or N110 without duplexing. That is also safe if done with common sense. I haven't shot a ramrod yet but there are many who have. The point is to pay attention at the range lest you end up with a bulged barrel like myself.

Doug

 

[CORVAIR]

I have shot some duplex, but I personally have no need to do so. My Savage HB likes Parker 275 BE's and 4759, as does my Nula.
2100-2300 fps is all anybody really needs for any game species with the right bullet and sabot selection.

I don't like the extra recoil and see no need for all the speed.

Safe, well yes these loads are safe if proper steps, volumes and loading methods are followed. There were some old 45-70 smokeless loads that were duplexed years ago, so they were the Pioneers of duplexing.

If you wish to pursue duplexing, just follow the recommendations of RB,SW and the others on the green board. They have a wealth of information on that subject.

 

[neonmoon]

why not duplex?

I have shot some duplex, but I personally have no need to do so. My Savage HB likes Parker 275 BE's and 4759, as does my Nula.
2100-2300 fps is all anybody really needs for any game species with the right bullet and sabot selection.

This is true as far as terminal benefit is concerned but shooting with increased speed allows the projectile to be affected by wind and gravity for less time thus less drop and wind drift. Also most have claimed increased accuracy with duplex loads. If we keep our shots to 150 yards or less the benefit of shooting faster is diminished but not elliminated.

I don't like the extra recoil and see no need for all the speed.

Safe, well yes these loads are safe if proper steps, volumes and loading methods are followed. There were some old 45-70 smokeless loads that were duplexed years ago, so they were the Pioneers of duplexing.

There is really nothing complicated or unsafe about it. Just pour in the ignition powder then the primary powder goes down behind it. Your done! Push the saboted bullet down the barrel like always and your good to go.

If you wish to pursue duplexing, just follow the recommendations of RB,SW and the others on the green board. They have a wealth of information on that subject.

If you go to the tips and hints section at the top of the green board you will see a section under "loads and powders". Click on that and the duplex loads are given there. Remember that recoil will be dependent on the amount of primary powder you choose to use.

Doug

 

[IndianaHunter]

You called it... It's all about choice... If you enjoy cutting paper then working up differnt loads is certianly a good time... As noted by Big 6x6 and Corvair, the combination of two or three bullets and two powders will provide outstanding results both in accuracy and terminal velocity... At this stage in my life a half day at the range sets me up for a season full of hunting...

Good luck...

 

[CORVAIR]

Re: why not duplex?

[quote="dougedwards]

This is true as far as terminal benefit is concerned but shooting with increased speed allows the projectile to be affected by wind and gravity for less time thus less drop and wind drift. Also most have claimed increased accuracy with duplex loads. If we keep our shots to 150 yards or less the benefit of shooting faster is diminished but not elliminated.

Doug,

From what I have read on the Green Board, 67 gr of N120 and a 300 gr Barnes Original will give you approx. 2300 fps and a good 300 yard load w/minimal temperature effects. That is a single powder load. Also, 4198 or R7 can be substituted.Additionally, since RB and SW have been avid shooters of duplex over the last several years, there has been some recent comment from them that single powder loads can certainly achieve the same effect as a duplex load.

The claimed accuracy of this particular load has been MOA.

A 300gr bullet at 2300fps does generate some "ouch" factor though.

 

[neonmoon]

Re: why not duplex?

[quote="dougedwards]


From what I have read on the Green Board, 67 gr of N120 and a 300 gr Barnes Original will give you approx. 2300 fps and a good 300 yard load w/minimal temperature effects. That is a single powder load. Also, 4198 or R7 can be substituted.Additionally, since RB and SW have been avid shooters of duplex over the last several years, there has been some recent comment from them that single powder loads can certainly achieve the same effect as a duplex load.
The claimed accuracy of this particular load has been MOA.

A 300gr bullet at 2300fps does generate some "ouch" factor though.

[/quote]

Yes.....that's exactly right. Duplex was developed because 250 grain bullets are very light weight projectiles to shoot in a 50 caliber bore. Although there have been some who have used duplex with 300 grainers it isn't necessary at all since single powders are very capable of pushing them to light speed without the risk of raising pressures to unsafe levels. Again.......duplex was developed for 250 grain bullets to shoot in a 50 caliber bore. Since then SW has developed some duplex loads to shoot 200 grain bullets from the 40 and 45 caliber bores.

 

[MK85Shooter]

From what I have read on the Green Board, 67 gr of N120 and a 300 gr Barnes Original will give you approx. 2300 fps and a good 300 yard load w/minimal temperature effects.

Corvair,

I want to clarify this statement. It may have been a typo but I just wanted to note that 67g of N120 is too hot of a load for 300g bullets. 62g is about the max before sabots start to blow. The correct range for N120 with 300g bullets is 58-62g depending on what your gun likes. 60g of N120 will usually give 2250-2350 fps depending on sabot fit.

H4198 @ 67g is good for around 2400 fps and is the sweet spot for many that use this powder. In my gun the trajectory of this load with a 300g Barnes Original SS and Harvester Black Crush Rib sabot is +3" @ 100, +1" at 200, and -14" @ 300 yds.

I have tried duplex with mixed results with speeds ranging from 2400-almost 2700 fps with 250g bullets. My gun seems to like speeds in the 2200-2400 fps range regardless of what bullet I'm shooting.

 

[MK85Shooter]

I wanted to address the about question about duplex loads being unsafe. If your powders are layered in the correct ratio they are perfectly safe. Tens of thousands of shots by seasoned veterans have proven that. The popular 14/61 duplex (N110/H322) is a proven load and if anything as RB has recently suggested might even be pressure sensitive.

However, to reverse the ratio by accident and say use 61g of N110 and 14g of H322 would likely result in something bad happening.

My suggestion if you want to try duplex is to get some advise and tutoring from someone that has an used it before and has an understanding of how it works.

 

[Rich De]

I got into these Savage ML's about 1 1/2 yrs. ago and in a month or so, started duplexing along with single powder loads. I believe there is nothing unsafe about the duplex load. Provided, as was said, you are using the right powders. 14/61 N-110/H-322 and NOT the reverse. It is not critical if, by chance, you accidentially put the slower powder (h-322) down the barrel first and then the faster powder.........or even if you put them in a jar an mixed them up! You just will not get the effect they are designed to do........and that is, "kick-start" the bullet to cause obturation. The duplex will also help in cold weather with the faster powder usually being the more easily ignited powder.
A while back, a number of shooters (on Dougs board) had complained of misfies with H4198 and 300 gr. bullets. So I figured, why not give it a little start. I wound up going with 10 gr. of 5744 UNDER 60 gr. of H-4198. The results? 2460 fps with Extreme Spreads in the single digit numbers. A number of shooters have tried it with similar results. RB who is the GURU over there, even commented that the load was about just right pressure wise for the 300 gr. bullet. His only complaint was a little ache in his shoulder
Another good duplex for the 250 gr. bullet is 10 gr. of N-110 under 60 gr. of N-120 which will put you right around 2600 fps and good accuracy and low ES's. One thing to note: on all my bullet/sabot combinations I strive for a diameter of .508 to .509" This size must be accompanied by a minor cleaning after each shot.........One 2x2 patch with four drops of Rem. bore cleaner in and out and one dry patch in and out. I also use an aluminum "cool rod" inbetween shots to keep the bore temperature down. I use mostly Red Crush sabots with the .452" bullets and the Black Crush with the .457-8" bullets. The MMP short black work well with the .452 if the velocity stays under about 2550 fps. If the fit is too loose, I "file-knurl" the bullet to "fatten" it up.
Richard

 

[CORVAIR]

From what I have read on the Green Board, 67 gr of N120 and a 300 gr Barnes Original will give you approx. 2300 fps and a good 300 yard load w/minimal temperature effects.

Corvair,

I want to clarify this statement. It may have been a typo but I just wanted to note that 67g of N120 is too hot of a load for 300g bullets. 62g is about the max before sabots start to blow. The correct range for N120 with 300g bullets is 58-62g depending on what your gun likes. 60g of N120 will usually give 2250-2350 fps depending on sabot fit.

H4198 @ 67g is good for around 2400 fps and is the sweet spot for many that use this powder. In my gun the trajectory of this load with a 300g Barnes Original SS and Harvester Black Crush Rib sabot is +3" @ 100, +1" at 200, and -14" @ 300 yds.

I have tried duplex with mixed results with speeds ranging from 2400-almost 2700 fps with 250g bullets. My gun seems to like speeds in the 2200-2400 fps range regardless of what bullet I'm shooting.

Yes, my mistake. I think I mixed-up the H4198 standard load with the N120 standard load.

67gr. of N120, not sure the pressure level, but there were some posts of others attempting this load level, feeling the xtreme ouch factor and backing off to the 60-63gr range. RB(on the green board) would have the PressureTrace facts for this information and that is what I would follow.
RB has not mis-steered anyone with his single powder or duplex loads, especially since he thoroughly Pressure tested almost all loads, with 250gr and 300gr bullets. I would not intentionally steer anyone to this high of an N120 load, so always check your facts before you spout, that means you CORVAIR! Sorry for the confusion and the late reply to this.