Hello,

So here it is, I have bought a Baikal / Spartan 12ga SXS 2 3/4" shotgun.
I have a set of the EAA / Tanfoglio 45-70 conversion tubes.
The appear to have proof marks, stamped in the tubes.
I am not familiar with Italian proof laws and marks.

How strong is this combination really ?

The SXS should be OK for 12ga Slugs, 1oz of lead at 1600 fps for 11,000 PSI
The tubes them selves should meet , 28,000 PSI, average 45-70 pressures.
The average SXS boxlock should be OK for +/- 32,000 PSI (mean pressure of most NE loads)

Would loads used from the table 2 of most loading books be OK in this gun ?
Table 1, Trapdoor 17,000 PSI, Table 2, Modern firearms 28,000 PSI,
Table 3, Marlin 44,000 PSI and Table 4 Mauser and No.1 56,000 PSI.

I am going from memory on the approximate pressures so they may be a little off,
but accurate enough for discussion purposes.
Let the flaming begin.

Build it and see.

George

George,
Agreed, but I want to see, without losing fingers or a nose! Does my logic walk, will the loads I made, at about < 28,000 PSI be safe ?

Since a .45/70 is never going to be a dragon slayer, why not just shoot 405 grain bullets at 1400 f.p.s. and be done with it. Shoot a hard cast bullet through the lungs of a black bear or an elk and they will expire quite nicely.

I had one of the insert deals and shot it at SAAMI specs. I enjoyed it. Lots of hogs died which is the perfect place to say, "You can't make a silk purse out of a pig's ear." Use it as intended and that's for about anything up to 1000 pounds (that doesn't <usually> bite back).

JudgeG

Is that to say there is only one SAAMI spec ? (28,000 PSI) Or are there multiple specs for this cartridge, dependant on action type?

I loaded to the specs at www.hodgdonpowder.com as follows:

405 GR. CAST LFP Hodgdon H4895 .458" 2.540" 40.0 1261 14,900 CUP 48.0 1453 18,900 CUP

My research shows one SAAMI spec at 28,000 CUP. Remington doesn't load but to about 18,000 CUP if I remember right.

My reasoning was that a double with iron sights (and my old eyes) is good only to about 100 yards, so why push velocites when about anything with soft skin will have two holes blowing blood, even at the 1400 fps that 18,000 CUP produces.

Nitro,
Lol...I had one too. When I got mine though, the instructions said recommended only for up "standard" SAAMI spec, which I would assume would be around 18,000cup. Wouldn't want to push it too much. I'd say stick to table 1.
Another point of thought is if it were able to consume some of the heavier loads, say around the "Marlin 1895" loadings, I would not think that would be too much fun getting it to shoot to point of aim!
Now I wonder what those tubes could do with they were reamed out to a 45-120...

quote:

Originally posted by nitro450exp:
The appear to have proof marks, stamped in the tubes.
I am not familiar with Italian proof laws and marks.

Barrels are not proven. Completed guns are.

quote:

The average SXS boxlock should be OK for +/- 32,000 PSI

Really? What makes you think that? That's three times what they're proven for.

quote:

+/- 32000 PSI (mean pressure of most NE loads)

No, that's 20-25% low for the flanged nitros.

quote:

Would loads used from the table 2 of most loading books be OK in this gun ?
Table 1, Trapdoor 17,000 PSI, Table 2, Modern firearms 28,000 PSI

With an unproven conversion on that action, I'd be nervous about Table 1.
-----------------------------------------------
"Serious rifles have two barrels, everything else just burns gunpowder."

Thanks for the input and comments.
My eyes are only 40ish, so 100yds is OK for me.
But I doubt, I will actually shoot anything at more than 40yds. All the deer in my backyard fell at 10-30 yds. I am hoping to get it to regulate at 1600-1800 fps, I really suck at judging distance.

Thanks

PS: By the way the monoblock has 65 Mpa and 18.4 VarCA stamped on it, Mpa I get, but VarCA ?

Nitro450exp,

I have one exactly as you describe. I put it together several years ago not being able to get my hands on the "promised" double rifle from EAA.

I mounted express rear sights on the thick rib and used an old pre-64 Win. Mod.70 front ramp sight. It was initially "fun" trying to regulate the tube inserts with the shim caps provided. It soon turned into frustration. The best I was able to get was 8.5" point of impact from each barrel at 50 yds.

I used very moderate loads with hard cast 300 and 400 gr. bullets. One caution, a friend wanted to try his "enhanced" loads. The primer blew out due to the large firing pin hole in the block that minimized the face support. The gas blew thru the firing pin hole and broke the stock, which was easily replaced by EAA.

So, my advice is keep the loads moderate.

Geoff

All,

Thanks again for the input, hope I have better results, I will find out this weekend.
I have made some loads with "the dreaded" 5744 and some with IMR 3031.
The 5744 being a basic nitro for black, are 300 JHP over 32 grains (1400-1500 fps) and 405 JFNSP over 25 grains (1200-1350 fps).
The IMR's are 300 JHP 52 grains (~1800 fps) and 405 JFNSP over 48 grains (~1700 fps).
I hope the IMR's are not too hot, I may have to pull them and start over.
I am still at the this will be fun stage, maybe you will see it in the classifieds in a few months.
Regards

If the proof marks are from the Italian proof bank, it should be quite strong. They supposedly test everything at one and a half times the maximum pressures it is supposed to handle. The weakest link is more likely to be the action itself I'd say.

Express,

Do know where I might find a picture or diagram of the Italian proof bank mark?
I will have to take a closer look at the insert tube, yes I agree the weak link is the action.
We basically have double chambers, a 45-70 ringed by a 12x70, 2 chambers should be stronger than one.
Thanks

Id say the one you are looking for is the first one on the list in this link.
Something like a start over a coat of arms/badge.

http://www.bancoprova.it/sezione.asp?num_s=7&num_ss=1&t...20di%20Gardone%20V.T

nitro450express

I have shot several deer with a 45/70.

The factory 300gr or equivelent handloads kill deer just fine.

If I was hunting black bear, elk or big pigs, I would use the Federal factory 300gr Nosler Partition, or this bullet handloaded.

By doing this you would have all game covered with loads that would not stress your 45/70 too much, and probably shoot to the same regulation.

Well did some shooting with it this weekend, lots of fun .
There are no signs of pressure with all the loads tested, I feel no need to continue with the AA5744, lots of residue.
The IMR3031 was fine and no welt on the shoulder with just a tee shirt and factory hard butt plate.
Groups are so so, with the left barrel about 1" higher than the right and about 4" apart at 25 yds.
Front blade needs to be raised 1/8", ~5" high at 25 yds.
Lots of fun.