Loading the 45-75---BP and Smokeless

[McLernon]

Is there any published loads for the 45-75. I presume I can use 75 gr FFg with a 350 or 400 gr bullet but don't know for sure. Also I have heard the the 73 which is very similar to the 76 design has been loaded with smokeless by may folks being carefull to not exceed BP pressures.

Any help will be appreciated

New to the 76

Mc

[Grizzly Adams]

Is there any published loads for the 45-75. I presume I can use 75 gr FFg with a 350 or 400 gr bullet but don't know for sure. Also I have heard the the 73 which is very similar to the 76 design has been loaded with smokeless by may folks being carefull to not exceed BP pressures.

Any help will be appreciated

New to the 76

Mc

Welcome to the fire, Mclernon.

Here is a thread with lots of interesting discussion and information regarding loading smokeless in the 1876.
http://www.cascity.com/forumhall/index.php/topic,17938.0.html

Check this thread for useful Blogs maintained by Members Hobie and Crotchety Old Grouch.
http://www.cascity.com/forumhall/index.php/topic,18580.0.html

Here is a starting point for you.    While this is not a published load (there are none!) it is a suggested load provided by Western Powders.  The 76 clones are proofed for smokeless powders, and Ten-X can and does provide a smokeless loading for the 45-75. Stick to BP velocities!

The correct bullet for the 45-75 is 350 grains #457122 is available from Buffalo Arms.

"Caliber:      .45-75 Winchester.

Case length:         1.895"

Case capacity:      5.189cc/79.92 grains of water

Pressure level:    <18000 psi.
Barrel length:      28"

Powder:           Accurate -- 5744.

Bullet weight:  350 grains.

Start load: 21.0 grains (1100 – 1200 Ft/p/sec)

Maximum load: 25.0 grains (1300 – 1400 Ft/p/sec)

NOTES:

It' important to note that:

Whenever Western Powders Inc do not test, and have actual data, on a particular caliber or caliber/bullet combination, we may in some cases provide some guideline. This information will be based on various procedures and calculations, or from other very reliable sources.

1.        SAFETY is our prime concern therefore:

1.1.   The loading data is conservative, especially regarding the minimum or start load to ensure a safe baseline to work from.

1.2.   The safety margin built into the start load might be more than the customary 10%.

2.        We strongly recommend.

2.1.   To always start at the recommended minimum "START" load.

2.2.   If at all possible, measure the velocity.

2.3.   Contact us again with the velocity data, so that we can verify, and correlate with our calculated/estimated data. The data should also be compared, with the typical velocity levels accepted in the industry, for that particular caliber-bullet weight combination."


The last line is important, as it reinforces what we have been saying in regards to working up safe loads.  Stay within the "typical velocity levels" for the caliber - BP velocities in this case, and verify what your doing with a chrono.

[McLernon]

Thanks Griz for the comprehensive reply. It is greatly appreciated.

One thing that occurs to me with spikes of the the same maximum value, is that if the 'time of loading' is closer to the 'natural period' of the restraining mechanism it is quite possible for one spike to illicit a greater dynamic response and corresponding greater deflection than another spike of the same magnitude but differnent natural period. That is, if the smokeless spike occurs in 20-40 microseconds and the BP spikes to max in 0.5 milliseconds there may very well be a difference in dynamic response of the mechanism. This is theory only, and the proof of the pudding is in the eating.

I think for the time being I will stay with BP pudding.

How much FFg BP can I load???

Thanks again Griz

Mc(chicken)

[Grizzly Adams]

Thanks Griz for the comprehensive reply. It is greatly appreciated.

One thing that occurs to me with spikes of the the same maximum value, is that if the 'time of loading' is closer to the 'natural period' of the restraining mechanism it is quite possible for one spike to illicit a greater dynamic response and corresponding greater deflection than another spike of the same magnitude but differnent natural period. That is, if the smokeless spike occurs in 20-40 microseconds and the BP spikes to max in 0.5 milliseconds there may very well be a difference in dynamic response of the mechanism. This is theory only, and the proof of the pudding is in the eating.

I think for the time being I will stay with BP pudding.

How much FFg BP can I load???

Thanks again Griz

Mc(chicken)

Well, as much as you can get in the case and still seat your bullet!   That will depend on what case you use, of course!

[Hobie]

Thanks Griz for the comprehensive reply. It is greatly appreciated.

One thing that occurs to me with spikes of the the same maximum value, is that if the 'time of loading' is closer to the 'natural period' of the restraining mechanism it is quite possible for one spike to illicit a greater dynamic response and corresponding greater deflection than another spike of the same magnitude but differnent natural period. That is, if the smokeless spike occurs in 20-40 microseconds and the BP spikes to max in 0.5 milliseconds there may very well be a difference in dynamic response of the mechanism. This is theory only, and the proof of the pudding is in the eating.

I think for the time being I will stay with BP pudding.

How much FFg BP can I load???

Thanks again Griz

Mc(chicken)

You have got to be an engineer... 

It would seem to me that you'd get differences with every brand and configuration (2F, 3F etc) of BP as well as with every BP sub not just with smokeless powders.  Substitute different bullet weights and diameters or temper and you'll have even more variables.   So many so that it hardly seems possible to exactly duplicate original loads.  They varied as well. 

I'm eager to read about your journey. 

[McLernon]

Yes Hobie, I am a mechanical engineer and I agree that the period of loading could be all over the place with different batches of BP and smokeless, but my impression is that most smokeless has a much faster pressure rise.

And then of course there is 777 and other subs which again would be different. I have tried 777 in my rolling block and it cleans up much easier than BP I find so might be leaning that way .

In any case it'll be a while before I put togetherany ammo as I dont have any tools or dies yet. Time to think and read

Thanks

Mc

[john boy]

McLernon:  The 45-75 round is:
Black Powder: a 350gr bullet and 75gr volume of 75gr FFg powder (as designated by the '75') in original caliber designation.
Reload - any large rifle primer - powder - 0.03 or 0.060 fiber wad - 350gr bullet. 
Smokeless Powder: key is to use a powder and charge that emulates a black powder 1380 velocity and 1485 energy or LESS.  IMR 4198 (24gr) and XMP 5744 (23 - 25gr) charges will emulate the black powder charge.  No wad is used when firing smokeless.

Re: H777 - to emulate a BP load data you might want to read about the powder on the Hodgdon website ... http://www.hodgdon.com/loading.html
All charges of Triple Seven or Pyrodex should be measured by VOLUME not weight. A simple, adjustable blackpowder measure is the correct tool for this job. All loads listed in this brochure are measured by VOLUME.

Triple Seven is a high energy product designed to provide the muzzleloading hunter with higher velocities when used in the same VOLUME as blackpowder. To duplicate a blackpowder load velocity using Triple Seven, you must decrease the powder charge by 15%. *See WARNING below.

Based on your questions and statements - believe you first should buy some reloading reference books, including a primer on how to load black powder.  Become familiar with the details and then start your loading.  Though no mention is made in this article about a 45-75, the basic 'how to's for loading BPCR loads is detailed and is an excellent read ... Introduction to BPCR Loading By Chuck Raithel

As for the bullet (a 350gr) ... read my post on your bullet thread

[McLernon]

Thanks again

Mc

[w44wcf]

McLernon,

I am a mechanical engineer and I agree that the period of loading could be all over the place with different batches of BP and smokeless, but my impression is that most smokeless has a much faster pressure rise.

Please see this post and you will find that is not the case with slower burning smokeless .
http://www.cascity.com/forumhall/index.php/topic,20300.0.html

w44wcf

[McLernon]

Hi w44wcf:

Me mudder used to say 'a word to the wise is sufficient'. I'll stay with cartridge Goex and learn how to clean up.

Thanks

Mc

[larryo_1]

Mclernon:
I really like 72 grains of Swiss 1½ under a 350 grain flatnose.  Has a bit of a bit at the shoulder but is very accurate and cleans up quite well when comparing it to Dupont or Goex.

[McLernon]

Thanks for all the responses. I have ordered moulds and dies will be ordered today along with a lubrisizer, sizing dle and top punch.

Mc