backwards duplexing

[Bullshop]

Gentlemen, and you others too ponder this for a bit it seems to have solved a little problem for me. I have this realy nice little Stevens 441/2 in 32/40 I have hade for a couple years but till now have never taken the time to try to figure it out. Worked with it saturday and right off things went fair but not good. Since Trail Boss worked so good in my Rem roller 38/55 for the next Waksupi match thought to try it again.
Hear is the problem I ran into. I dont size cases for these guns so rely on the powder/wad column to locate the boolit correctly. The correct load will have the case filled to the point that with the boolit just sitting on the powder its right where I want it in the throat when chambered.
The problem was it took about 10.2gn of powder to do that but that was a bit too hot. It was begining to crater a CCI LP primer, and rem primers were so bad it had to shear them to open the action, ug rem primer = soft cup.
The most accurate charge was 9.7gn but that left the boolit too far in the case. I was compensating for this with styro wads and it took 5 to get the right length.
That created a new problem. I think the wads were compressing differently from shot to shot when chambered. They chambered with moderate thumb pressure but I was getting a perfect verticle string of over 2" at 100 yards. The horizontal was about 2 boolit holes wide.
What I needed was a filler that wouldnt compress much, but what. I got the goofy idea to try a reverce duplex. I didnt want the main charge to burn differently just to fill the case more so instead of putting the other powder under the main charge I put it on top. The other powder I used was Pyrodex RS. I wanted to use BP but its awfully hard to come by here.
Anyway with the 9.7gn main charge of Trail Boss and a .3cc dipper of pyro on top then 1 styro wad on that seems to have done the trick.
There was no noticable increase in pressure and there was no more verticle stringing.
As I was testing I was loading lots of three and five and stepping out to try them since the shootin shack is only 50 yards from the loading bench. I was running out of time for the day but it was looking perty good when the last 4 lots of 3 went into about a nickle size hole. The last couple shots I was able to pick out the tacks holding the target.
Oh yea the mold is a Saeco 168gn tappered FN cast in straight ww this morning. Lubed with Speed Green in the bottom 1 of 4 grooves. I tried lubing 1, 2, and 3 grooves but it worked best with 1.
There ya go fellers the new wave in fillers, good ol BP. Now go spearment!
BIC/BS

[Bullshop]

Oh yea in case anyone is wondering how good my eyes are to pic out tacks at 100 yards with an 80 year old iron sighted rifle shootin them plain base lead boolits that folks tells me all the time how they will plug up a barrel. Well the secret is I just flipped down that tang sight and peared right through that big ol 15x Unertal Programmer.
Gona have to try this one in one of the Waksupi matches if I can get it shootin real good!
BIC/BS

[454PB]

Why BP? Why not a medium burn rate smokeless like WW 760?

[Bass Ackward]

Dan,

I have erased this two times at attempting to post a reply here.

I can't do it without sounding condescending. My main concern is allowing a free floating bullet to establish case volume on a practice that is unpredictable as hell.

May God be with you.

[joeb33050]

Breech seating with the Stevens 44 1/2 is easily done with a plugged case. The action will close and push the case so the bullet is seated. Fiddle with plugged case length to get best accuracy.
joe b.

[45 2.1]

Dan-

I'm useing the heavy RCBS boolit with about 4 to 7 gr.( no notes handy) of WW231. It sort of lobes the boolit downrange into one hole thats hard to measure actual group size on. I size the first 1/2" to hold the boolit. You might try that also as the CBA benchresters are useing very light charges to do the same thing.

[Bullshop]

454pb
I thought a smokless filler would contain more potentail energy and might raise pressure more than I wanted. I know from duplexing smokless a kicker of fast under a main of slow does get the slow burning a bit faster. This would be the same thing accept the in this case the fast charge would be bigger than the slow.

45 2.1
That wont work for me cuz it wont fill the case. I would have to size cases, or breach seat the boolit and plug the case. I looked at a breach seating tool from the Stevens guy and I cant afford it.

Joeb33050
I am afraid using the action to seat boolits will eventualy loosin the action. I once had one that was so loose the underlever would fall open. It would not stay closed on a round unless you held it closed. Am I right or wrong?

Bass
I dont care about condescending. I respect your opinion and want to hear it. I load all my match ammo this way. Most often the boolit is sitting on a hard or pre compressed powder column so the whole thing acts like a fixed cartridge just with a long OAL. I am not shure what you are saying. Is it that the powder charge may be compressed and there by reduce case capacity and raise pressure? I tried the load with just the TB and no wad with the boolit fully in the case. At that OAL there would be no contact with the boolit in the rifling and at that length there are no pressure problems.
Although I have not tried to compress it TB seams like it will compress easily. I had thought about different depths of compression in seating a boolit in the lead this way but with this type of tappered boolit designed for breach seating there is little resistance in chambering. It would take an obstruction of some sort to change the seating depth to any degree and that should be noticable in chambering a round with thumb pressure. It is possible I guess for fouling to build up in fromt of the chamber and slowly change things with seating. With these small charges of smokless you dont see that.
Could you explain a bit more on your concern. I am obviously missing something. Dont worry about my feelings, I think I know a lot about this stuff but I am shure not a know it all. I got lots to learn!!!
BIC/BS

[powderburnerr]

Bull shop
you can make a breech seater with a case and a short rod .drill out the back end of the case insert the rod to length and fill with lead or epoxy , or a piece of wooden dowel will work as well ........... Dean

[Bass Ackward]

Is it that the powder charge may be compressed and there by reduce case capacity and raise pressure?

Although I have not tried to compress it TB seams like it will compress easily.

It would take an obstruction of some sort to change the seating depth to any degree and that should be noticable in chambering a round with thumb pressure. It is possible I guess for fouling to build up in fromt of the chamber and slowly change things with seating. With these small charges of smokless you dont see that.


Dan,

You got my main concern which was something that compressed easily could change pressure radically. And TB should be vulnerable to compression. I certainly wouldn't count it as a "hard" powder column. I missed the part about thumbing them in, but no matter. Any judgement for safety here should be judged not on this application. But on whether you would feel comfortable teaching this lesson to junior. Because you are. He is watching and craves good results to be just like dad. Created a monster you did. :grin:

The problem with reverse duplexing comes from the wave action that may never show up with your brass or primers. There are examples of guys blowing off muzzle breaks with cast and the brass still looks like pressures were quite mild. Dan at Mountain Molds has been recording secondary wave action using just a single powder that reaches the 107,000 psi level easily after a 55,000 psi chamber peek.

Assuming for a moment that his method of measurement is flawed, it still manages to be close on the initial pressure levels. When you reverse duplex, you actually would seem to be reinforcing the second wave effect. Forward duplexing on the other hand rises the initial pressure that would cause more of the powder to burn in the initial pressure wave and thus minimize secondary effects.

Glad I took some time to think about it.

[Bullshop]

Bass
I understand exactly ZERO about that wave stuff some of you fellas talk about. I do kinda like the obstructed barrel thingy of the big bang problem. But that aint why Im here. I got somethin for ya to ponder. If you have access to Parker Ackley's handbook for shooters and reloaders please turn to page 521 and check out the load Dick Casull put up in 45 colt cases.

Talk about your wave!! triplex loading yehaw!!! Look at them powders Unique. 2400, and Bullseye all in a row and held together by compression.
Look at them velocities from a 45 colt in a handgun, and then a 92 carbine. Yessir that is some kinda wave alright.
Dont get mad at me Bass I dont mean nuthin bad at ya. I know you were right and I thank you for the heads up. To easy sometimes to get lost in what were doin and make a no no boom boom!!!
I tried breach seating some today and found the seater only had to push them in about another 1/10 past what they would fall in to be flush with the case mouth. Since I had them seated more than 1/10 in the case yesterday they werent even touching so were not compressing the powder at all.

Joeb33050
You were right on that 231. I poured a case full of lead today to make a simple seater. I found it takes very little pressure to seat those tappered bullets the additional 1/10 past what they fall into the chamber. At about 6.5gn 231 it started lookin good. Out of the last three lots of three 7 went into .5" and two were out an inch. It may still nead to be adjusted up or down a 1/10 or it could be my bench tecnique. I am finding this perty little filly to be very temprimental to any changes in holding position or pressure. She wants to be held only a certain way and thats it. I need to refine my holding as much or more than the load. Thanks for that load tip, at 6.5gn per shot thats over 1000 shots per lb. I will keep plugin along and eventualy might get them flyers figured out. OH yea wanted to mention this thing is realy sensitive to primer changes too. Every change in primers moved the group 2 to 3" on the target. The best one so far has been the CCI-BR2.
BIC/BS

[joeb33050]

454pb

Joeb33050
I am afraid using the action to seat boolits will eventualy loosin the action. I once had one that was so loose the underlever would fall open. It would not stay closed on a round unless you held it closed. Am I right or wrong?

BIC/BS
I don't think so. I've had two 44 1/2 Stevens rifles and breech seated with an adjustable plugged case for many shots and no problems with looseness. I don't understand why breech seating would loosen the gun up. I'll ask CPA.
joe b.

[Bass Ackward]

Dan,

I understand. And I don't take offense. We all have a path we choose to walk. Somebody has to break new ground. All this is is a recount of my experience.

One day I asked 6 ol time gun men and reloaders to figure out a duplex load for me using two powders. These men were just as familiar or more than me with the powders, caliber, reloading etc. All had read everything I knew of to include PO's books. And some of these guys were my mentors in the craft.

The idea was to see if well experienced minds could logically think alike and therefore produce something that should be .... safe. After a few days, I received 6 answers. None of the 4 loadings was close to my logic. And none of those 4 were really close to any of the other responses. The last two responses were warnings. One gentleman said, it only takes one mistake. The second gentleman gave me a can of powder with no label on it and a note, I don't know what it is, tell me how it works out.

At that point, I began to doubt my ability to think "better" than people that had more experience than I did. So .... I stopped the practice. My duplexing any more is forward and just a few grains for ignition.

[45 2.1]

Dan-

Joe didn't suggest the WW231. If your getting flyers, change your boolit temper to softer or breach seat a little deeper.

[Bullshop]

452.1
Sorry about the mix up! Thank you! Looks like I wont be trying today kinda wintery looking out there.
BIC/BS