round nose bullet excess pressure woes

[uk roe hunter]

Yesterday i loaded up some 308 win rounds using some old stock nosler solid base round nose bullets. I started at the speer books minimum of 45 gr and worked up in 1 gr increments. with re15.

in the past i have used the speer manual for .223 .243 7mm08 308 win, 270 30-06. I have never seen any pressure signs even at max. however i always have used spitzers.

the published max for the 150 gr bullets is 49 gr.

At 48 gr there were some pressure signs, but only mild. at 49 gr it blew the primer!

The pressure was clearly high.

all powder loads were accurately wieghed.

is it because the shanks are longer relatively speaking? are nosler bullets a tiny fraction bigger?

uk

 

[ranger335v]

"is it because the shanks are longer relatively speaking? are nosler bullets a tiny fraction bigger?"

Lots of possiblities, those are some. But who knows? It happens without any certain indicators. That's why we have to "develop our own loads."

What you experienced is why the manuals always say that if you change any part of the load, even primer, bullet or powder lots, start over, go low and only move up ONLY if there are no over pressure signs. I would have stopped at 48 and backed off a bit from that.

 

[uk roe hunter]

47 is the load we will go with, it was most accurate

 

[Remo-99]

Yesterday i loaded up some 308 win rounds using some old stock nosler solid base round nose bullets

Another possiblity, if your in the UK, check those 'old stock' bullets to ensure that they are not intended for .303british, which are slighty larger diameter than .308"

That also would give early signs of pressure(under max loads), working up loads.

 

[interlock]

thanks for the input guys,
remo99 whist old stock they were sealed box with 30 cal 150gr. i am quite confident that they are right. i think that squeezing a .311 bullet down a 30 cal barrell would give massive pressure signs like the bolt going through my shoulder.

ranger,
your points are well taken.

Thanks

interlock
(uk roe hunter in the office......don't tell the boss)

 

[USSR]

uk_roe_hunter/interlock,

Manufacturer of brass used?

Don

 

[NCsmitty]

uk_roe_hunter/interlock, I have viewed the on line data from Alliant and indeed, they list 49 gr of Rel-15 as the max load with 150gr bullets. I also cross checked Ammoguide's listings and found a couple loads with Rel-15 that's showing 46gr as MAX with 150gr Noslers(no type listed) and 47gr MAX with Barnes 150gr. If you are using mil spec cases that could be adding to the problem.
Your choice of the 47gr charge is probably near MAX with the components that you're using.

NCsmitty

 

[Ol` Joe]

The ogive of RN bullets will contact the lands much quicker then spitzers and need to be loaded to a shorter oal. You were not jamming them in the leade were you?

 

[ants]

• Even if still sealed in the box, I would weigh a few to verify the weight.
• Ol Joe is absolutely on target with his OAL querry.
• I generally blow primers because the case has been loaded too many times and the pocket has stretched, not because the load was too high; maybe you should check on that.
• My apologies in advance, this is not meant to be demeaning. But I was once dumb enough to load the wrong powder, and it sure went Bang when I pulled the trigger. I also once set the scale wrong (one whole grain higher). Maybe you should double check those details, my friend.

When we use round nose soft point for deer out here in the West (western part of North America) we generally don't need to get max velocity. Round nose bullets are very heavy hitters, and usually open up rather quickly. They don't need much velocity. If we do need velocity because we plan on very long range shots, we go to a boat tailed spire point with low ballistic coefficient, not round nose.