Vihtavuori N340 for .44-40?

[eisenhower]

Yep, Starline brass, Winchester primers, and have tried Hunters Supply, Lightning and Acme .427 RNFP bullets so far.

The Hunters Supply shot 100% clean of any leading - the other two left a touch just in and past the forcing cone. Hunters Supply are coated with something called Slick Coat which may account for the lack of leading. The .430s I've ordered are theirs - I will try them at both .430 and sizing them to .429 (though that may negate the advantage of the Slick Coat by removing it.)

[bryanaustin]

Jul 4, 2024 19:17:13 GMT -5 eisenhower said:

As I say, I have slugged bore and chamber mouths to the best of my ability and limitations of my caliper.

Bore slugs .4275-.428 depending where I measure on the slug. Cylinder mouths measure between .4295-.430".

Like I said...... .427"/.428" will work fine.  You can fine-tune for accuracy as you go.

Now, if you use .429/.430" hard cast diameter lead bullets and push them out if the .428 bore, expect higher pressures than published.
If you use .427/,428" soft lead, with normal loads, the pressures will expand the lead into the grooves and seal the bore. Creates less pressures and may improve accuracy.

It all depends on what you are looking for.....and remember...whatever road you choose, enjoy it and go from there. While you are out shooting, most are sitting reading the forum ;-)

[eisenhower]

So, here's my question on that.

I've been shooting 5.8 grains of Titegroup with .427 bullets. If I want to shoot .429 bullets in the same pistol, how much should I reduce that 5.8 grain charge to try to keep the pressure about the same?

[Encore64]

Personally, I doubt any. If it makes you feel better, chronograph your previous loads. Then back off .5 grn and work back up.

Anybody who's ever sized bullets knows it takes very few FPE to take a couple thousands off a bullet.

Besides this, you really aren't even doing that due to the throat size in your cylinder.

You'll get a much better gas seal with a properly sized bullet. It's really just Revolver 101...

[bryanaustin]

Jul 6, 2024 9:20:00 GMT -5 eisenhower said:

So, here's my question on that.

I've been shooting 5.8 grains of Titegroup with .427 bullets. If I want to shoot .429 bullets in the same pistol, how much should I reduce that 5.8 grain charge to try to keep the pressure about the same?

What a lot of people may not realize is the difference from old time loading and modern loading. Back in the day the factories and handloaders loaded to the max....and then some when able. It is all in the manuals and articles as well. Over time, from WWII to the 1970's, manufactures and handloading data scaled back from max loads, and new generations (fill in the blank here) of shooters was born. 

The reason modern data is the way it is for the 44-40 is due to the smaller bores and popular over sized bullets use, much of what was not available back in the day. Much data has a fairly liberal margin of safety built in for such issues.

Hodgdon shows  5.0 to 6.2 grains of Titegroup with a .428" diameter RNFP lead bullet. The information they do not offer is the barrel's bore diameter or the type lead used. The barrel length is 20"....thus velocity is higher than what it would be in a revolver if you use a chronograph to test such loads. The velocity and pressure they give is 1,117fps @ 12,900 lbs of pressure for 6.2 grains of Titegroup powder.

So how can we use this data without guessing? We can't. A bit more than reloading 101! This is why it is best (reloading 101) to use load data from Lyman's 49th type manuals that lists such more complete data.

Official test barrels are tight and a bit more strict on measurements. Arms or barrels that are not true test barrels may a bit more liberal in measurements. Some data manuals shows tests performed with actual firearms, shows the bore diameters and bullet data. This is a bit more reliable than just a "lead bullet" and .xxx" bullet diameter.

However, if you do all the right stuff, a .429" (200gr) hard or soft cast lead bullet, using 5.8gr of Titegroup in a .428" bore should not surpass their (Hodgdon's) max pressure data listed for 6.2gr.


Using a chronograph can be useless when comparing apples and oranges...

[eisenhower]

Thanks for the info, guys. I don't have a chronograph, and am debating buying one, as once I work up loads for this pistol, I don't anticipate doing a bunch more reloading for other calibers. I started this reloading journey simply because .44-40 is so difficult to find off-the-shelf anymore (not to mention expensive), and I want to keep my Colt SAA shootable for the future.

[bryanaustin]

I grabbed a Lyman 49th and thought I would share the information that can be rather important when using data with different components to attempt to achieve the same goal.

Page 369 lists revolver data

Test Barrel - 6" Universal Receiver (official test barrels) - .428" bore. The conflict with new Receivers (link provided in RED) is that they are set up for use with the Piezoelectric sensors (11,000 PSI MAX), not the copper units of pressure (13,000 CUP MAX). 

Case Trim - 1.295"
WLP primers


Titlegroup

• 427666 - .429" 200gr #2 alloy, 1.580 AOL...6.4gr max, 973fps @ 12,700cup (not psi)
• 427098 - .429" 205gr #2 alloy, 1.580 AOL...5.8gr max, 964fps @ 12,200cup (not psi)
  
  

I never "pressure tested" Titegorup so I do not know if there MAY be a safety margin with the published pressures. However, here are the results of powders I did test. My test results are amateurish but realistic and linier, aligning with load manuals and factory ammunition.

[bryanaustin]

double post, edit error