Changing Maximums

[Jim1 AB]

The other thing that I'm a little surprised with is this 300 WM I'm loading. It's a older Tika. I've loaded for this rifle since the owner bought it. The loads as mine WERE, past tense here, hot to say the least. He's about one grain less than mine. Last minute he says he wants to go hunting this year. I have a bunch of 165 Sciroccos loaded up for the Remington 300WM of mine and I know these are not even close to hot. Same velocities as we have shot the 180s before. First shot blows the primer. What the hell. I go get my 300 and check the load it's fine. I take the Tika up and build a few very light loads to check pressures. I can't get close to the published max loads. Maxing out in this rifle now is like half way between min and max. The barrel really needed a good cleaning but that hasn't improved things much. Of course this is not really a problem, 100 ft/sec is not to be worried about but why has this rifles pressure maximums changed. I haven't tried an other bullet but that may be some thing to look at.

Jim

 

[Antelope_Sniper]

You might want to have a smith take a look at it.
Sometimes this is the first sign of worse things to come.

 

[Jim1 AB]

I'll keep I eye on the brass he shoots to see if anything changes. He'll probably only shoot a hand full of rounds so he will just have to make do this year.

 

[rick smith]

If these were loads from your rifle, could be a headspace issue between the two rifles. How many times has the brass been fired?Rick.

 

[DrMike]

If I understand your post, cartridges that were loaded for your Remington when fired in his Tikka blow the primers. It could be as simple as OAL generating higher pressures. If you are using neck-sized cases from your Remington, they may be impinging on the lands of the Tikka, or you may be crushing the neck. You need to provide more data: OAL, case length, number of firings, etc.

 

[barthowes]

+1 from me on DR mike's reply. could be many different things, my best guess is OAL.

 

[Jim1 AB]

Full length resized cases, bullets have to be seated deeper in the Tika because of the magazine length. It's all older brass maybe fired five or six time. Rick headspace issues?? How would that work??

Jim

 

[Antelope_Sniper]

Sorry I didn't read that correctly.

Going from a Remington to a Tikka with reloads is a BAD idea.

Tikka's usually have a tighter throat, which will generate higher pressures.

 

[Jim1 AB]

As I said we use to be one grain of powder difference in the loads. Five years ago. Something has changed????? I did the loading for both.

Jim

 

[rick smith]

Headspace issues in belted mags between different rifles can go from too little to too much. Belted mags headspace on the belt until you have fired them and then your FL die should be set to headspace on the shoulder. If you measure to the datum line on a fired case vs a new unfired case in both rifles you will find if that is the problem. The main problem with this is usually case head seperation but it could be a pressure problem with brass that has been fired multible times.Rick.

 

[Jim1 AB]

Sorry Rick I'm just not fallowing your thinking here. How would headspace manifest it's self in pressure issues. And brass that's been fire a lot.... hardening??

I'm thinking it may just be the Sciroccos. The Tika may not be able to deal with the harder bullet as well as the older, fired a billion times Remington. I'm going to try another bullet today and see what happens.

 

[rick smith]

Brass work hardens from expansion/contraction. The more it is fired/loaded, the harder it gets. That is why we anneal the necks. The chamber dimentions of the two rifles could be quite different in relation to the datum line on the shoulder since the chamber was cut for headspacing on the belt not the shoulder. Are you are sizing to headspace on the shoulder or belt? When changing from one rifle to another it is always best to use new brass in the different rifle. If his rifle has shot this bullet before without a problem, something else should be suspect. If the cases were loaded from the same lot of powder/primers and the brass has been fired/sized for your rifle then I would suspect the brass as the problem.Rick.