stevehud58
Member
Well I tried some 200 grain 375s and still couldn't get past 2100 fps with Lil'gun powder. I was starting to see some flattening of the primer so I quit on upping that load and switched to H4198 that I actually had book data for. With a max load of 4198 I still could not get past 2100 fps for most shots though there were a couple random rounds over 2200. The more powder I used the lower the average fps would be. It just didn't make sense. So I bought some 270 grain gas checked lead bullets and expected somewhere around 1825 for my max velocity with that bullet. I beat it by 100 fps averaging 1925 fps. So the big lead bullet worked just fine. Why???
I knew I had a long free bore, from the case mouth to the rifling, but if it was 375 diameter that shouldn't be a problem. So I did a chamber cast and the free bore was indeed the problem. My gas pressure was going by the Hammer bullets in the free bore due to their relatively short bearing lengths. I have included a picture of the casting with 3 bullets. 185 Hammer in front of the casing, a 200 grain Hammer below and a 270 lead bullet above with the casting above that. The bullets are placed where they would first contact the rifling. You can see that the lead bullet is touching the rifling while the base of the bullet is still in the casing.
In my description of it, below, I have changes the length measurements from thousandths into rounded off fractions, so to make it easier to visualize.
The rifle chamber is 1/8th inch longer than my 375 casing. That's even longer than any 38/55 case. Its diameter mikes out at .400. Next is the free bore at 3/16ths inch in length. This mikes out at .380 along its length. Then where the rifling starts it is still .380 but tapers up to 375 in about anther 3/16ths inch. So that is a total of about 1/2 inch to get to a 375 bore diameter. What looks like rifling in the photo of the casting, is not rifling. It is something odd in the photo. Where the point of that mark stops is where the rifling actually starts.
I have been told that some 94s were chambered this way to facilitate using 38/55 cartridges with .380 bullets in the gun. They would just get squished down to 375 without building too much pressure for the lighter built casings. I was also told that some of the 94's were marked both 375 and 38/55 to show this style of chambering but some were not. Mine is obviously one of those. It is only marked 375 Winchester.
So the pressure force is just slipping past the bullets in the large free bore as there is not enough length of "shank bearing area" to seal the pressure until the bullet reaches the rifling. I am assuming the reason I was getting pressure signs of the flat primer while still not getting velocity with the 200 grainers, was that the peak pressure was reached while the bullet was still in the casing. Then it was lost in the free bore before the bullet reached the rifling.
I think I have to call it quits on this venture of using brass bullets in this gun. Even if I could talk Steve into making me a bullet long enough to work out, it would be heavier than what would work out for any velocity I needed. Even if I could get 2000 ft fps it would be down to 1800 at 100 yards and the expansion window would be closed. My hopes had been to have 6.5 pound rifle with peep sights 3/4 inch off the bore, that would have been 3" high mid trajectory and 3" low at 200 yards while still having over 1800 fps and 1500 ftlbs energy at that distance. I am going to have to be happy with a 125 yard rifle and heavy lead bullets.
I knew I had a long free bore, from the case mouth to the rifling, but if it was 375 diameter that shouldn't be a problem. So I did a chamber cast and the free bore was indeed the problem. My gas pressure was going by the Hammer bullets in the free bore due to their relatively short bearing lengths. I have included a picture of the casting with 3 bullets. 185 Hammer in front of the casing, a 200 grain Hammer below and a 270 lead bullet above with the casting above that. The bullets are placed where they would first contact the rifling. You can see that the lead bullet is touching the rifling while the base of the bullet is still in the casing.
In my description of it, below, I have changes the length measurements from thousandths into rounded off fractions, so to make it easier to visualize.
The rifle chamber is 1/8th inch longer than my 375 casing. That's even longer than any 38/55 case. Its diameter mikes out at .400. Next is the free bore at 3/16ths inch in length. This mikes out at .380 along its length. Then where the rifling starts it is still .380 but tapers up to 375 in about anther 3/16ths inch. So that is a total of about 1/2 inch to get to a 375 bore diameter. What looks like rifling in the photo of the casting, is not rifling. It is something odd in the photo. Where the point of that mark stops is where the rifling actually starts.
I have been told that some 94s were chambered this way to facilitate using 38/55 cartridges with .380 bullets in the gun. They would just get squished down to 375 without building too much pressure for the lighter built casings. I was also told that some of the 94's were marked both 375 and 38/55 to show this style of chambering but some were not. Mine is obviously one of those. It is only marked 375 Winchester.
So the pressure force is just slipping past the bullets in the large free bore as there is not enough length of "shank bearing area" to seal the pressure until the bullet reaches the rifling. I am assuming the reason I was getting pressure signs of the flat primer while still not getting velocity with the 200 grainers, was that the peak pressure was reached while the bullet was still in the casing. Then it was lost in the free bore before the bullet reached the rifling.
I think I have to call it quits on this venture of using brass bullets in this gun. Even if I could talk Steve into making me a bullet long enough to work out, it would be heavier than what would work out for any velocity I needed. Even if I could get 2000 ft fps it would be down to 1800 at 100 yards and the expansion window would be closed. My hopes had been to have 6.5 pound rifle with peep sights 3/4 inch off the bore, that would have been 3" high mid trajectory and 3" low at 200 yards while still having over 1800 fps and 1500 ftlbs energy at that distance. I am going to have to be happy with a 125 yard rifle and heavy lead bullets.
