It does seem a bit slow for that short of barrel but I was hoping some one has had experience with the two and compared them in a Tanfog 4.5 gun.
I have a 7 inch 1911 and a Stock III with the Poly rifled 4.75 inch barrel. My chrono is showing a consistent higher velocity between the 4.5 and the 4.75 and over 100 ft/sec faster on the 7 inch barrel. All with the same assortment of ammo (both factory and reloads)
the current off the web data below is confusing as it has N105 for the 155 but not 3N38, and 3N38 for the 165. I suspect its like some one on here said, testing is expensive and they can not test all combinations. I do not have 3N38 in the chart below but I did look, the 3N38 is a bit faster but has less PHE. this suggests that it might work better for the 155 versus the 165. the caveat is the barrel length, the VV data is for a 5.5 Barrel. The 3N38 has lower heat then Blue dot with about the same Burn rate suggests the 3N38 might be a good compromise.
Blue dot, BE-86 and AA#7 are all doing ok, but I am not getting velocities that match the published data, and Fed 150 primers are getting flat even then. The same load (even used the same piece of brass and same lot of bullets (Horn Jacket 155, old stock not XTP) and CCI 300 are not flat........but we all know the Fed 150 are softer.
Primers as a indicator for pressure in handguns is always iffy due to the lower pressures involved, even in 10mm.
With the above caveat in mind I did work the loads with BE-86 higher until the CCI 300 got as flat as the Fed 150, velocity still did not match the published data (it was higher). Published data is for 5 inch barrel for the none VV powders, but my 4.75 is close enough to 5 inches I would expect the velocity to be better.
But I seldom get "LOADING BOOK" velocity from my reloads........ I am risk adverse and seldom have the same exact components the reloading books are published with.
AND......powder is not the same lot to lot.
The 4.5 gun is a Witness Steel owned by a friend, he wants the 155 XTP for CC..........this will not be a load he shoots a lot of, but I still want a load that is not stressing the gun. I have chrono data for both Buffalo bore and Underwood in his gun and my STOCK III (assorted bullets), the velocities are lower then what those two companies publish (not surprised given the short barrel). The 4.75 barel was a bit faster then the 4.5, I wonder if its barrel length or the Poly Rifling, if any one has real data or info, please pass that along.
He is willing to buy ammo, but that makes my Dillon feel marginalized.
https://www.vihtavuori.com/reloading-data/handgun-reloading/?cartridge=62