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EXCESSIVE PRESSURE
Rosie
Member Posts: 14,525 ✭✭✭
Bought a 91/30 with matching numbers some time ago. Ordered a couple of tins of the Bulgarian 762x54R which I believe has around 187 grain bullets. The fired cases look great after firing but the primers show a little oozing back into the firing pin hole. Not much but noticeable which tells me excessive pressure. Any Ideas why? This gun looks like it was never issued and the rifle grooves looks great.
Comments
I can't say what they are doing without a picture, but recently firing of my 91/30 shows a very large primer hole which may give the impression you speak of. High pressure will generally be shown on the primer as a double dimple and sometimes a shiny crest on the edge(s) of the dimple. You can see high pressures as well on the cases just like reloading. A shiny head, a matting-like pattern very low down from the shoulder on the base of the case. And, of course, hard to remove from the chamber. If not hard to remove from the chamber it might just be your rifle or those particular bullets that are giving an impression of high pressure. You may need to chrono the loads to see what they are doing or just wait until it gets cooler to shoot them. Hope that helps if any.
As to case taper; 7,62x54, .348 Win, .33 Win, 8mm Lebel and some other
mostly older cartridges have very steep case tapers on the order of .015"/" for easy extraction. For that reason cases and chamber need to be dry of oil to minimize unnecessary thrust on the bolt face.
The Moisin Nagants are very strong rifles.