AB/BT

[HeathSexton]

The Nosler book max for H414 and the 55gr NBT in .243 Win will blow primers and you have to take a hammer to the bolt on my friend's .243. He thought since it was in the book it was ok.

Starting at max is never a good idea.

So why didn't Nosler have blown primers or a stuck bolt on thier rifles? Personally I don't start at max, for accuracy reasons, but, I have NEVER had a problem with ANY max loads EVER. Had a stiff bolt, but it never got stuck closed. sounds like to me he didn't measure the charge correctly.

You're probably right, the fact that it was weighed out on a calibrated RCBS scale and double checked on a 505 beam scale would show that it was weighed wrong. I have a .260 that won't allow near max charges with a couple of powders, but I probably weighed thos out wrong too.

 

[boolit]

The more I thought about a stuck bolt I do remember working a bolt open on the bench... using the bench to force open the bolt. It's been a long time.... I assume it was a hot load.

I believe I haven't experienced this is because I haven't used slow powders to see it. I just looked through my targets and data... and only have one load with H414. That's for my .243. As for my .270 well that's another story. I use O'Conners load of 60 grains of H4831, without starting low... no problems. 4831 is at the bottom of the list for slow buring, but not rock bottom.

I saw a guy on another site who loaded RL25 at max on his 1917 enfeild, blew apart his stock, and shattered his reciever.

Guess I 've been fortunate, and so has a guy at my gun club. The Lord has been looking after me. Sorry if I went off the deep end, I'm glad I have this site to come to. Thanks guys for putting me in line.

 

[tddeangelo]

I think the issue here is that anytime you change any component in reloading, it is safe practice to back the load off just a bit and work back up. Changing bullets in a load that may be at the threshhold of maximum safe pressures could be the defining factor that causes a pierced primer. By all means, if the two bullets shoot close enough for the OP (which should be achievable) then it's a fine idea. Safety first!

Couldn't have said it better myself. No harm in being safe and controlling risk as best as possible.

Boolit, every rifle is different. A slighty tighter or looser cut chamber will raise or lower pressures quite a bit. That is why they have min and max loads. Scotty

A slighty tighter or looser cut chamber

Can't see how that would effect pressure.... how much of a difference in a chamber size would effect pressure? Maybe dimensions in the bore, but not chamber. Correct me if I'm wrong, but you better have something solid.

Spend some time on Google and look up "Boyle's Law".

Here's the cliff notes version (from Wikipedia):

"For a fixed amount of an ideal gas kept at a fixed temperature, P [pressure] and V [volume] are inversely proportional (while one doubles, the other halves)."

Change the chamber size, and you change the volume. Change the volume, and you change the pressure (when all else is kept constant).

 

[boolit]

thousands count I guess? How many thousands? Can a case expand to effect pressure?

 

[chet]

chamber dimension, barrel length, groove diameter, and barrel condition (fouling) can all add up to a dangerous situation. A load perfectly safe in your gun might blow my gun apart.
I have two kimber rifles. And both of them show obvious signs of too much pressure with most factory ammo. Comparing my fired brass to others, it's easy to see that both kimbers have quite tight chambers. Both barrels are fairly short, and squeeky clean, and they're button rifled so they can't possibly be undersized bores. So I attribute the high pressures strictly to chamber dimension.

 

[JD338]

I think the issue here is that anytime you change any component in reloading, it is safe practice to back the load off just a bit and work back up. Changing bullets in a load that may be at the threshhold of maximum safe pressures could be the defining factor that causes a pierced primer. By all means, if the two bullets shoot close enough for the OP (which should be achievable) then it's a fine idea. Safety first!

Couldn't have said it better myself. No harm in being safe and controlling risk as best as possible.

Boolit, every rifle is different. A slighty tighter or looser cut chamber will raise or lower pressures quite a bit. That is why they have min and max loads. Scotty

A slighty tighter or looser cut chamber

Can't see how that would effect pressure.... how much of a difference in a chamber size would effect pressure? Maybe dimensions in the bore, but not chamber. Correct me if I'm wrong, but you better have something solid.

Chamber size will indeed have an effect on pressure, along with several other variables.

JD338

 

[SJB358]

I think the other bigger variable I am really learning is the case! Using the Nosler cases have made me revamp my load work a touch. Been using WW cases for so long, it was a little learning to make my loads right. Scotty

 

[boolit]

I think the other bigger variable I am really learning is the case! Using the Nosler cases have made me revamp my load work a touch. Been using WW cases for so long, it was a little learning to make my loads right. Scotty

make my loads right...? Using the Nosler cases have made me revamp my load work a touch

Hows that Scotty?

 

[SJB358]

The Nosler brass has a different internal capacity which when used in conjunction with published load data needs to be changed up a bit in order to find the mins and maxs. It is not a big deal, but it is something to be aware of. Scotty