MKIII* Lithgow General Questions

[smle addict]

As far as the protruding primers, that might be a sign of low pressure cartridges. I cannot speak to the specific loads you were using, but generally speaking, if light loads are used, the pressure will be insufficient for the case head to be driven back against the bolt face. In this case the walls of the case expand to grip the chamber and the primer is forced back, out of its pocket, until stopped by the bolt. This might also be accompanied by dark, sooty case necks/mouths.
With higher pressure loads (factory ammo for example), the head is forced back against the bolt and the primer goes with it. No protrusion is possible as the pocket/head move together, along with the primer , all to be stopped by the boltface.

I handload some very light target loads for an old lee-metford of mine. Cast bullet in front of a light charge of Trailboss. Very low recoil, and the primers all back out of their pockets a few thousandths of an inch. Case mouths a little sooty.

This is not to be confused with primer extrusion, where a high-pressure load causes the primer to "flow" and flatten.

A picture could tell us plenty. I have shot several thousand rounds of 303 mk 7 surplus and have never seen a primer back out (not a low pressure load, and pocket crimped). I few years back, I bought some old Winchester 180 grain ammo at a gun show. Fired that stuff and the primers did back out slightly, and the load did feel light.

Hope this helps.

Information

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[Daan Kemp]

Skew trigger guard: twisted/not flat? From the photo it seems to bottom out on one side and sits proud on the other.

[nijalninja]

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I have examined the guard closely, but I don't have the experience or the keen eyes to spot if it is the case.

[nijalninja]

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Here we have our mixed brass. I really am thinking it is these downloads since I used this stuff in a few different rifles and got the same result, some of this brass may be from my No4 but its all the same.

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And trigger guard. Looks pretty straight to me. If it is skewed then it would be in the recess of the wood correct?

[Daan Kemp]

From the photos the trigger guard looks OK. Lay it on a flat surface to see if there isn't a gap somewhere. If there isn't, fine.

If the trigger guard isn't seated evenly in the wood something in the fore end isn't right. Without handling the rifle I can't say more. If seats evenly no problem.

If all are as they should be it's the photo causing the questions.

[nijalninja]

Yeah the trigger guard recess could by all means be bearing unevenly as I have been poking around in there trying to make sure there are no odd contacts acting side to side to side on it. Possible I've nicked something.

[smle addict]

Yup, from the photos of your cases, I would say they are low pressure and wouldn't worry about the primers backing out. My guess is if you'd bump up your loads in half-grain increments, you'd gradually see those primers stay in their pockets. If you're happy with that loads performance, I say fire away. The loads for my Metford all look like that, and its only a good load for 50 yards, but its cheap and fun.

[nijalninja]

Sounds good to me smle. I guess I don't have to radically headspace all my rifles after all. Thanks for that.

[freedomintheskies]

Can you get your hands on a set of go/no go gauges? They would be the definitive indication of a serviceable headspace.

Your cases and primers show a low pressure load, as others have stated. It will not hurt anything IMHO.

[nijalninja]

I don't have a set laying around but I want to to get them.