The UK's Finest Independent Forum for Shooters and Gun Owners. Est 2010.

On the last batch of .303 (second batch), I noticed that some of the primers were sticking out after firing. So on the last (3rd batch) lot, I tried not to 'over-do' the pocket cleaning, and gave the primers a good push in - still quite a few are doing the same: Sorry closest focus I can get - the primer has pushed out a tiny bit, but not flattened - I'm sure it's not a pressure problem, as it's only 39 grn of Vhit 140; and although the rounds shoot well at 200, the drop from 200 to 400 is about 6'!

Is it a head space problem ?

Sure it could be have it checked
sincerely
Filippo

I have never experienced this at first hand but I have heard it put down to NOT ENOUGH pressure...IE the primer might backout a little under firing pressures BUT the pressure is not sufficient to expand the case enough to push the head back onto the bolt face thereby reseating the primer.

Excessive headspace also a potential ..... I understand that this is common in .303 with different bolts being available to adjust it?

you can get over pressure signs like this with too much powder as well as too little powder

Don't think that's a problem.

Out of interest what sort of primer seating tool do you use and did you visually inspect the primers after they were seated and is this happening to every round fired? Do you have any reloads from the same batch that are unfired that you can check?

I had exactly the same problem with HXP brass and Magtech primers using a Lee primer tool and because the case holder has a slight cut out it is possible to slide a case out that does not have a fully seated primer. Doing it by feel alone they felt to be very well seated at the time and it was not until I have primed a few a stood them on end and noticed they wobbled that I realised what was happening. Not sure they would ever have been shot in this condition as Christel usually checks the cases before she fills them and I check again once built.

41grains of N140 is a good load in all my 303 rifles try working up your load see if it makes a difference.

I am on 39.5 grains N540 on my No4 Mk1 and no such problems plus it holds the drops on my No32 Mk1 quite well.

DaveT wrote:Excessive headspace also a potential ..... I understand that this is common in .303 with different bolts being available to adjust it?

Yes adjusting headspace on an Enfield bolt is relatively easy (for a gumsmith) to adjust - When I changed from 7.62 NATO to .308 Win in my Enfield conversion, Fultons simply changed the bolt head, which took up the 6 thou slack and cured the problem.

The problem for me though is that the next time I'll be at Bisley is the Trafalgar - and I'll be using the rifle all day...I'll have to nip in at the end and get it checked...but if I have to leave the rifle there, it'll mean a 3/4 hour drive just to pick it up again :roll:

ovenpaa wrote:Out of interest what sort of primer seating tool do you use and did you visually inspect the primers after they were seated and is this happening to every round fired? Do you have any reloads from the same batch that are unfired that you can check?

I had exactly the same problem with HXP brass and Magtech primers using a Lee primer tool and because the case holder has a slight cut out it is possible to slide a case out that does not have a fully seated primer. Doing it by feel alone they felt to be very well seated at the time and it was not until I have primed a few a stood them on end and noticed they wobbled that I realised what was happening. Not sure they would ever have been shot in this condition as Christel usually checks the cases before she fills them and I check again once built.

I do use a Lee primer - but make sure they are all seated properly - I check each one visually straight away, and if in doubt check it's in by putting a small metal ruler across the case head to make sure it's 'flush'. On the last 50 I made, maybe 3 or 4 didn't seat propperly first time - so I put them back in the tool and pushed them harder...1 or 2 needed the use of both hands to get them in (don't worry, safety glasses worn...).