Author Topic: Vihtavuori Tin Star  (Read 7438 times)

Offline Bryan Austin

  • Top Active Citizen
  • *
  • Posts: 880
  • Liked:
  • Likes Given: 0
Re: Vihtavuori Tin Star
« Reply #40 on: April 13, 2020, 02:31:17 pm »
I did, a blistering 974fps!!!!!!

Offline Bryan Austin

  • Top Active Citizen
  • *
  • Posts: 880
  • Liked:
  • Likes Given: 0
Re: Vihtavuori Tin Star
« Reply #41 on: April 13, 2020, 02:36:52 pm »
A while back I testes some Trail Boss with my PressureTrace strain gauge system.

6.4gr  945fps @ 7,224psi (maybe 8,000cup)
9.3gr 1,250fps @ 15,182psi (maybe 18,000cup) Magma design bullet sits on top of powder with no compression. Bullet seating depth .300"

Bulk Powders vs Bulky powders
It is my belief that Dupont manufactured the first smokeless powder used by Winchester in the 44-40. John Kort dissected several cartridges and found what he thought was Dupont No.2. He experimented with this powder, about April 2013, which he discovered to be as advertised by replicating such loads. Directly replacing black powder per volume, 17gr of Dupont No.2 was a "BULK" powder for the 44-40, produced 1,300fps but pressures are unknown to me. Looking at published loads in the 1930's, the 44-40 rifle loads that replicate 1,300fps show 10,000cup with certain powders like 2400 and Unique and possibly Sharpshooter and Lightning powders using the 200gr JSP. It has been reported that today's IMR-4227 has the same burn rate but yet 17gr (less volume) only produces 1,127fps @ 10,643psi (12,500cup). My tests using 19gr of IMR-4227 gave me 1,296fps with a 427098 @ 11,000psi (13,000cup) better replicating early smokeless powder loads in both velocity and chamber pressures. Better yet, 22gr with a Winchester JSP (.4255") gave 1,386fps @ 12,035psi (14,000cup).

The second powder I believe to have been used would be Laflin & Rand's Smokeless Sporting Rifle Powder...also using 17gr for the 44-40. Both Dupont and Laflin & Rand bulk powders appear to be "blonde" in color. This powder was only available for a year or less when taken over by Dupont.

What I believe to be the third powder used by Winchester was Laflin & Rand's "Sharpshooter" or at least Dupont's "Sharpshooter" by 1903. Both powders were perforated disc or very thinly sliced tube powder. Although a "bulky" powder, it was not a bulk powder but was also specifically advertised as a black powder replacement and noted as such on the powder cans "For Black Powder Rifles". Ironically 19gr of Dupont and Hercules Sharpshooter, by 1914, was noted as a High Velocity load. Sharpe's 1937 handloading manual notes 19.6gr of Sharpshooter produced 20,000cup. However, Sharpe also notes that 17.3gr of Sharpshooter (1937) with the JSP produced 1,305fps(normal factory velocity) @ 14,000cup (maybe 12,000psi) and 14gr producing 1,260fps but does not list pressures but would certainly be less than 14,000cup. It has been said the 2400 has a similar burn rate. If so, Lyman's 49th lists 18gr of 2400 with a Speer 200gr SJHP (#4425) @ 1,380fps and 14,600cup. 20gr of 2400 with a Speer 200gr SJHP #4425 @ 1,638fps and 19,000cup. My results differed as expected showing 1,300fps with only 16gr @ 9,000psi (maybe 11,000cup) and 1,672fps with 20gr of 2400 @ 15,618psi (maybe 18,000cup).

My testings with Trail Boss as a Bulky powder

Published 6.4gr max with an Acme Magma bullet produced 900-1000fps (945fps)@ 7,224psi with great plinking accuracy but also did well out to 200 yards but may not retain enough energy for harvesting game.

However, a caseload were the bullet sits on top of the powder like black powder, held 9.3gr. This load gave me 1,250fps but at a cost of 15,182psi which could be close to 18,000cup.

Thus the burn rate vs velocity doesn't match very well when comparing Trail Boss to early Dupont bulk powders or even later bulky powders used for high velocity loads.

In 1913, Dupont introduced SR80 (Sporting Rifle). It was a granular type powder. similar in appearance to Dupont No.2 smokeless powder but was faster burning and was not a "bulk" type powder. It's burning rate was in the same range as Sharpshooter. Sharpe's 1937 does not list chamber pressures for this powder.

“Sharpshooter” and "SR80" fueled millions of .44-40 smokeless factory cartridges up until at least the 1950’s (SR80 was discontinued in 1939) when ball powders began appearing on the scene. Winchester switched to a ball powder similar to the old W630 which also has a similar burning rate to 2400. Remington continued to use “Sharpshooter”. I recently dissected some Winchester Super X cartridges and discovered the same type ball powder with a 12.8gr charge. Winchester last offered this load in 1978, then in 1979 Winchester began using a disc shaped pistol powder of which I weighed at 8gr. This is when the advertised velocity dropped from 1,310fps down to 1,190fps.


My "go-to" powders that seem to equally replicate velocity and pressures and most importantly accuracy are;

1. 25.8gr of Reloader 7 with a 220gr lead bullet @ 1,361pfs and 12,000psi (est. 14,000cup). Factory standard velocity loads. (1894-1978)

2. 24gr of IMR-4227 with a 200gr JSP @ 1,590fps and 18,000psi (est. 22,000cup). Factory standard High Velocity loads. (1903-1938)

These are the only two powders that give the greatest accuracy, retain energy (out to 200 yards and greater) and produce the least pressures in my tests.

Overview
Dupont No.2 vs IMR-4227
17gr of Dupont No.2 "BULK" powder produced 1,300fps but pressures are unknown

17gr of IMR-4227 (less volume) produces 1,127fps @ 10,643psi (12,500cup)

22gr of IMR-4227 with a Winchester JSP (.4255") gave 1,386fps @ 12,035psi (14,000cup)



No Data
17gr of Laflin & Rand's Smokeless Sporting Rifle Powder - no data found



Sharpshooter vs 2400
14gr of Sharpshooter (1937) with a 200gr JSP produced 1,260fps no pressures listed but would certainly be less than 14,000cup

17.3gr of Sharpshooter (1937) with the JSP produced 1,305fps(normal factory velocity) @ 14,000cup (maybe 12,000psi)

19gr of Dupont and Hercules Sharpshooter (1903-1914) was noted as a High Velocity load @ 20,000cup.

16gr of 2400 with a Speer 200gr SJHP #4425 @ 1,300fp @ 9,000psi (maybe 11,000cup)

18gr of 2400, according to Lyman 49th, with a Speer 200gr SJHP (#4425) @ 1,380fps and 14,600cup

20gr of 2400 with a Speer 200gr JSHP #4425 @ 1,672fps @ 15,618psi (maybe 18,000cup).


 

SMF spam blocked by CleanTalk

© 1995 - 2020 CAScity.com