Is there any real danger of an overly high pressure following book loads?

[rayporter]

nearly all reloaders have more than one book and we compare loads constantly. the books almost never match!

another instance of the difference in barrels and chambers.

when i order 6mm barrels i have a choice of ordering .236 or .237 diameters. personally i have had some problems with .236 barrels and have come to prefer a .237.

 

[minengr]

Depends on the age of the book. I have the book my dad used back in the 60's. I wouldn't trust those numbers.

 

[black dawg]

I have never been too concerned if the recipe matches.......like same bullet at same oal, same brass and primer. But even then will start a little low.

If the components dont match the load data exactly, then I start much lower.
Did have an experience with some light 270 varmint type bullets loaded at mid load (according to several different sources), that were over pressure. Shot them in spring weather and everything was ok. When it got warmer had popped primers and very sticky extraction. And this was with brass that I have used many times. ?????

Always wondered how factory loads can perform decently?

 

[TX_Diver]

Wondered this myself after comparing 2 books a while ago.

For a 77gr SMK in .223 w/ N140:
Sierra starts at 19.5 and goes to 22.3 (bolt gun)
VV starts at 21.0gr and goes to 24.7.

So the book max Sierra load is near the low end of the VV data... I haven’t made it to pressure signs yet with LC brass up to 23.1, but with FC brass had very slightly flat primers at 21.7. Maybe related to brass prep based on some discussions, but either way it definitely seems to be a case of everyone’s mileage varying...

 

[Harvey_NW]

I'd like to point out, for those that may not know, those numbers all correlate and changing one can change them all. Most commonly COAL/CBTO/jump. A load that's spec'd as safe book max at SAAMI COAL is presumably "safe" in all SAAMI spec chambers, but if you grab that charge and load it to .010" off the lands you'll get much higher pressure. Working up and identifying pressure at a set distance from the lands and planning on decreasing the charge and working backward (decreasing COAL/CBTO) from there is the best way I've found to develop safe loads.

Having said that, guys like Satterlee talk about starting at book max in YouTube videos all the time. I think it's a little negligent and they forget they're not shooting the same quality of rifle as much of their fan base. I find it best to cross reference a few different sets of data like others have said, and find that safe starting charge for yourself. You waste about 8-12 rounds shooting a ladder, and if you throw a chrono over it you're gathering velocity data. Worth it.

 

[Sekora]

nearly all reloaders have more than one book and we compare loads constantly. the books almost never match!

another instance of the difference in barrels and chambers.

when i order 6mm barrels i have a choice of ordering .236 or .237 diameters. personally i have had some problems with .236 barrels and have come to prefer a .237.

I wonder if this is the problem I am having. I have a Remington 6mm from the 80's that maxes out on pressure much sooner that the books say it should. I have shot it through a chronograph and the velocities are matching the book data for the powder charges but I am getting flattened primers and sticky bolt release. I have found a powder that seems to do much better with the pressure and accuracy (H1000), but have not got it totally tuned in yet.

Answering the original question; Start low and work up. All rifles behave differently.

 

[WCB]

Does anyone have any examples of either catastrophic damage to an action or injury to the shooter with a load that was within book values, without something else being awry?

I have seen ammunition confirmed well under SAAMI specifications blow primers and "cause" damage in A LOT of rifles. Why would it do that if it was under SAAMI spec....because something else went "awry". "catastrophic" damage is pretty subjective. I have seen rifles basically turned to match sticks and the shooter maybe have a bruised ego and arm. I have also seen rifles where an extractor was simply blown and the mag blown out the bottom otherwise the rifle looked brand new, but the shooter had cuts on the face and a broken hand or shrapnel in arms hands etc. Take chances wherever you would like but no I said the fly.

 

[dla]

Usually I have a target velocity in mind and I select a powder/bullet combination that looks like it will get there with the lowest pressure. I usually check multiple data sources as well as experience of others on forums.
I load up a few with the starting load and run them over the chronograph. Adjust for barrel length, brass, etc. and see if the velocity/brass/primer look sane. If sane continue, if not then stop till I figure out why not.

 

[woods89]

I have seen ammunition confirmed well under SAAMI specifications blow primers and "cause" damage in A LOT of rifles. Why would it do that if it was under SAAMI spec....because something else went "awry". "catastrophic" damage is pretty subjective. I have seen rifles basically turned to match sticks and the shooter maybe have a bruised ego and arm. I have also seen rifles where an extractor was simply blown and the mag blown out the bottom otherwise the rifle looked brand new, but the shooter had cuts on the face and a broken hand or shrapnel in arms hands etc. Take chances wherever you would like but no I said the fly.

That's good info. Both those situations would fit my definition of catastrophic.

 

[MajorSpittle]

I know this is an old thread but will throw my $.02 in.

I got a batch of ReLoader 17 that is hot in my 30-06 compared to the book data I was using. I may have been using different brass then the book but primer/powder/bullet/COAL was the same and I was getting the book velocities with roughly 3 grains less powder and out of a rifle with a shorter barrel.

I had 3rnds loaded in 1gr increments to book max and tried to shoot all of them because I was stupid and didn't want to tear them down. It was a hot 95 degree day with a hot rifle from shooting. I never had heavy bolt lift or swipe marks, but had cratered flat primers and ejector flow marks on the brass before I loaded the book max load and had a primer blow out and etch the bolt face of my Tikka.

I imagine if I would have loaded the bullets long and had a bullet a into the lands that things would have been worse.

Always start low, that way if YOU make a mistake or your equipment/components are out of spec..... you will at least have a chance to find out before it is a bad day at the range. There can be significant lot to lot variance with some powders and there are some which are very sensitive to temperature ( which is why I think you see some max loads with certain powder/bullet/cartridge combinations well below SAAMI Pressure spec )

 

[TX_Diver]

Think I posted this earlier, but I had some loads that were 1gr over minimum in the 30-06 with H4350 and had immediate pressure signs.

I now start 1-2 gr below minimum and load 1 shot each up to a bit past max before loading up a few rounds of each. I still need to go pull like 47 more rounds after that first experience...

RL17 is getting me book velocities at well under book loads. Likely low capacity LC brass.

 

[N.AmericanTrophyHunts]

Just today I loaded up 140 SMK and 7828ssc in fresh brass to fire form out of my PRC. Book data showed 48 grains being staring load and 53.3 max. I loaded 100 at 50gr, 40k off lands. First round yielded extreme heavy bolt lift, ejector marks, cratered primers the whole bit. Grabbed some other proven handloads I had and they shot just fine.
What I’m getting at is regardless of book max and data, your chamber will tell you where pressure is.

 

[Wrench]

I've stuck two bolts in my life that scared me.....a 300roy and a 375h&h. The h&h had really thick brass and the 300 was too long ago to dissect.

My 308 win on book data for a 175 crossed the chronograph at 2875....several times. The book was SUBSTANTIALLY slower.

It can happen.

 

[Centralcoastca]

I tend to load a min load and mid load and if the min load acts like it should I’ll jump to mid and work slowly from there. I figure it’s not worth a few extra bucks blowing it up starting at max plus plenty of guns work better under max so I might find a spot I’d skip over. I don’t know anyone who starts at max but I know a few that creep incrementally from starting loads to see every little thing on the way up. Those guys usually end up closer to max but always find great loads somewhere. I consider them smarter and more patient than me and I am working towards being like them. In my opinion it’s not a place to try and save a few dollars and time since there’s the chance you’ll have to back off a little to find your accuracy and end up spending more time and money chasing your tail while taking a possible risk.