Large Velocity Variations With Lebel Revolver Reloads

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Lahti

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Hello,

I picked up an Mle 1892 French Ordinance (Lebel) revolver in 8mm and haven’t had much luck with my reloads. I made up 12 rounds to try using 3.5 grains of Unique powder, 110 grain .327 cast lead Bulletsand factory Fiocchi brass and primers, COL 1.330, and got a range from 373-594 feet per second. (Data for each round and which chamber it was fired from at end of post).

The revolver is in good mechanical function despite its age, and my charges, seat depth, etc.. were double checked. It was not simply a matter of carelessness in loading. There was a fair bit of partially burnt powder present after every shot, very sooty so I appear to be getting incomplete combustion.

A little additional information, the revolver was slugged and has a bore measurement of .327 inches. Fiocchi primers are used as factory fiocchi ammo led to a squib, so I am using the primed brass.

Does anyone have any suggestions as to how I might go about fixing this?
I was thinking of trying a different type of primer, or using cast .330 bullets (next size up available). I do not want to simply increase charge as this is near the upper end of what is recommended, and I have been advised to use this powder as it is a go to for antiques. I’m only looking for 600 feet per second or so, the problem is the consistency.

Any help would be appreciated,

Thank you

Data

1- 462, 432
2-501, 454
3-594, 504
4-513, 415
5-373, 517
6-465, 528
 
Try red dot. I've had more consistent velocities with it in my 455webley mk2. I think it will also take up a little more space in the case which should make ignition better
 
Since he doesn't want to use more powder maybe just a magnum primer and/or heavier crimp. He is getting inconsistent deflagration so increasing the starting pressure is the easiest way to get back on track. I also notice he is using bullets of the same diameter as the bore, it's standard to go at least .001" over to create a proper fit. I wouldn't let Red Dot anywhere near an antique myself, it's an extremely fast and energetic powder.
 
Hello,

I appreciate the feedback so far. From what I’ve read on a fairly extensive CGN forum (https://www.canadiangunnutz.com/for...olver-all-you-need-to-know?highlight=Lebel)on loading for this pistol, 2.8 grains-3.2 grains of Unique was considered the proper load range, with 3.5 considered hot which is where my hesitancy comes from.

Sounds like my best bet to start would be trying an increased crimp (they were lightly crimped) with the load/brass I have, or backing off on my starting load some, using magnum primers and working up?

Failing at that, the next size up for cast Bullets available I have found is .330, would that be too drastically oversized? Unfortunately I’m not in a situation where I can cast my own yet, so I’m stuck with what I can order.

I’m not completely opposed to another powder, however I tend to try my best to be cautions and it seems like unique was the only powder out there everyone seems to be in agreement is good for antiques.

Thank you
 
Then go with green dot. They are both powders recommended for 455 webley mk2 with reduced loads to match the black powder load as well as other black powder cartridges. Lots of documentation to support this.
 
If it chambers properly .330" should be fine. I have used bullets sized much larger than the bore in various rifles with no issues. Work up as always. I'd still start with a strong crimp, it's probably all you really need if you only had a light one to begin with.

jhnvan said:
Then go with green dot. They are both powders recommended for 455 webley mk2 with reduced loads to match the black powder load as well as other black powder cartridges. Lots of documentation to support this.
Click to expand...

I'm not arguing it won't work, just that putting in slightly too much could be more than something like a Lebel pistol could handle. I am not aware of the OP's experience or his particular reloading setup. I actually use a Red Dot analogue called Promo since I got a large quantity for free. It's a better powder than it gets credit for but I'd save it for modern firearms myself.
 
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jhnvan said:
Try red dot. I've had more consistent velocities with it in my 455webley mk2. I think it will also take up a little more space in the case which should make ignition better
Click to expand...

I was going to suggest less of a faster powder such as Red Dot.

That said, when trying to remain in the 550-600 fps range (bore obstruction alley), even the very fast powders are operating at the bottom end of their effective pressure range and wide variations are unavoidable.

I'd reset your expectations to 650-700 fps and say good-bye to your challenges.
 
Hello,

I appreciate all the feedback so far. I will try heavier crimp to start, magnum primers and then lastly if needed add more power and update results here in case it is able to help anyone else.

Good point about that being near the speeds bore obstructions can occur, hopefully my current charge with better crimp/primers will be enough to bring me up to 650-700. That is nearer to the original velocity of around 715 feet per second.

Thanks again
 
Lahti said:
Hello,

I picked up an Mle 1892 French Ordinance (Lebel) revolver in 8mm and haven’t had much luck with my reloads. I made up 12 rounds to try using 3.5 grains of Unique powder, 110 grain .327 cast lead Bulletsand factory Fiocchi brass and primers, COL 1.330, and got a range from 373-594 feet per second. (Data for each round and which chamber it was fired from at end of post).

The revolver is in good mechanical function despite its age, and my charges, seat depth, etc.. were double checked. It was not simply a matter of carelessness in loading. There was a fair bit of partially burnt powder present after every shot, very sooty so I appear to be getting incomplete combustion.

A little additional information, the revolver was slugged and has a bore measurement of .327 inches. Fiocchi primers are used as factory fiocchi ammo led to a squib, so I am using the primed brass.

Does anyone have any suggestions as to how I might go about fixing this?
I was thinking of trying a different type of primer, or using cast .330 bullets (next size up available). I do not want to simply increase charge as this is near the upper end of what is recommended, and I have been advised to use this powder as it is a go to for antiques. I’m only looking for 600 feet per second or so, the problem is the consistency.

Any help would be appreciated,

Thank you

Data

1- 462, 432
2-501, 454
3-594, 504
4-513, 415
5-373, 517
6-465, 528
Click to expand...


These old revolvers have a range of chamber and bore dimensions. Info from owners is bore sizes ranging from .323" to .330". I've measured myself bores from .325" to .328".

The variations also exist at chamber/throat. "Maybe" the bullet is smaller than the throat so that there is blow-by, resulting in a reduction in chamber pressure and the cause of inconsistent powder burn and variations in velocity. A faster powder may or may not help in this situation, in any case I am hesitant to use Bullseye/IMR700 or similar fast burning powders in 130 year old metallurgy.

The first thing I'd do is scrap the fiocchi primers.

If your chamber will allow it (some won't), a fatter bullet might reduce blow-by and aid in powder combustion without requiring a heavier load. One of the mantras of cast bullet shooting is the largest bullet to chamber cleanly is usually the best shooter. It's a theory only.

I might consider increasing the load in small steps, a 10th grain per step and a cylinder full per step while recording velocity to see if consistency might improve. You might be on the edge of having reliable bullet obturation and a small increase in pressure might take you over the threshold. But keep in mind it's a theory and not a prediction. How far to go would be up to you but when the highest recorded velocity gets into the 700 fps range I would not be going much further.

Using a chronograph like you're doing is the best way to estimate pressure without access to a ballistics laboratory. The French 1892 has a higher pressure standard than most revolvers of that time but don't expect warnings from "pressure signs" in fired brass. These old guns were designed for such low pressure that they may reach detonation level before you see any pressure signs in fired brass.
 
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The thought of blow-by in the cylinder throats is interesting. Peak pressure is achieved before the bullet exits so any would definitely be detrimental.
 
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