Newbie reloading question

[Jonathan_S]

How can velocity be a sign of pressure? Short barrels, long barrels, cut rifling vs button, number of grooves, lapped or not, difference in throats, how many rounds have been fired...etc. too many variables for velocity to be even close to a pressure indicator.

Bolt lift, brass mark or over expansion, primer appearance etc. seem pretty reliable.

[jasnt]

I feel they are all tools no one should be more important than the rest.  You have to look at all the variables.  I've seen slow loads with preasure signs and hard bolt lift. I've seen smoking fast loads that had no sign of over preasure. 

[bobcat]

More pressure equals more velocity. I'm no expert, I only go by what I read from people who have more experience and knowledge than I do. In this case, John Barsness. If you're interested do a search for something like "pressure and velocity Barsness."

What you will find is that John Barsness recommends not relying on all the traditional signs of excessive pressure, as those things are not reliable indicators. If you see those pressure signs, you've often already gone way too far into dangerous territory.

According to him the best tool for a handloader in working up a load is a chronograph, and as I already said, you stop when you reach the max book charge, OR when you reach the max book velocity, whichever comes first.

[hogslayer]

On my first facotry rifle I found best accuracy at 3 grains over book max.  1.5 grains under actual max.  Brass lasted 8 firings before pockets got loose. My custom chamber is 7 grains over book max. Found pressure at 8.5 grains over book. I have also had tight barrels that hit pressure sooner. Some barrel companies such as Broughton are known for making faster barrels with there canted lands. Not trying to be a jerk, but you can believe what you have read, and I’ll believe what I have done.

[Karl Blanchard]

On my first facotry rifle I found best accuracy at 3 grains over book max.  1.5 grains under actual max.  Brass lasted 8 firings before pockets got loose. My custom chamber is 7 grains over book max. Found pressure at 8.5 grains over book. I have also had tight barrels that hit pressure sooner. Some barrel companies such as Broughton are known for making faster barrels with there canted lands. Not trying to be a jerk, but you can believe what you have read, and I’ll believe what I have done.

  spot on

[theleo]

On my first facotry rifle I found best accuracy at 3 grains over book max.  1.5 grains under actual max.  Brass lasted 8 firings before pockets got loose. My custom chamber is 7 grains over book max. Found pressure at 8.5 grains over book. I have also had tight barrels that hit pressure sooner. Some barrel companies such as Broughton are known for making faster barrels with there canted lands. Not trying to be a jerk, but you can believe what you have read, and I’ll believe what I have done.

And if you run them through a chrono you'd see velocity spiking as you approach max. PO Ackley also noted case design plays a large part in traditional pressure signs. Cartridges with a steep shoulder and minimal body taper start showing pressure signs later than rounds like the 30-06. Waiting for the traditional pressure signs is what leads guys to say their 280ai is just as fast as any 7mm Rem mag, they're not. They are just loading the 280ai to significantly higher pressures. The fact they're running loads to the same velocity as that of a cartridge with 13gr of additional powder capacity, is a good indicator of high pressures. 

[bobcat]

I'm not really sure what's being said here. Do you not use a chronograph as a tool in helping to work up loads and to help determine when you're approaching a maximum charge for your rifle? Chronographs are so cheap that I think all reloaders should use one. Personally, in my reloading I almost never see any of the traditional pressure signs that people talk about. I may go 1 or 2 grains above the book to see if groups improve but if I'm already getting good groups and my velocity is where it should be, I don't see a need to try to push it any further.

[theleo]

More pressure equals more velocity. I'm no expert, I only go by what I read from people who have more experience and knowledge than I do. In this case, John Barsness. If you're interested do a search for something like "pressure and velocity Barsness."

What you will find is that John Barsness recommends not relying on all the traditional signs of excessive pressure, as those things are not reliable indicators. If you see those pressure signs, you've often already gone way too far into dangerous territory.

I agree relying on traditional signs usually means you're well beyond safe when they emerge, but more pressure does not always equal higher velocity. I can safely load a black powder vintage 45-90 with a 350gr bullets to around 1,400 fps without issue or I could easily load it to around 1,000fps and split the barrel using the same bullet.

[Curly]

I agree with the pressure = velocity premise.

The problem with published load data is it rarely matches up with your particular OAL you may want or other particulars.  So, it is hard to go by what a book may call max.  But the books are good points of reference. 

The bullet and powder manufacturers have tested the loads and published the info.  If Alliant says they reached max SAAMI pressure and got X velocity at that pressure, then it really doesn't matter a whole lot what powder charge they got that velocity at, but you can be pretty sure that if you are exceeding that velocity with your loads then you are probably over SAAMI max pressure.  A reloader would use the data as a starting point and work up loads over a chronograph.  If no chronograph, then it probably would be prudent to stop at book max even if you aren't seeing the signs of over pressure like flattened primers and sticky bolt lift.    (Or you could just slowly work up until you get signs like flattened primers and sticky bolt, but just know by then you could be around 70,000 psi).

[jasnt]

I try not to talk about going over book max in a beginer reloading thread but one thing to remember is that the books load is for working in any rifle. Seating depth is often a lot of jump. Brass volumes are different, there also often on the side of caution due to lawyers.  If your not expirences enough to recognize preasure signs early you should not go over book max.  After you've gained the expirence needed then you can squeeze that extra fps out to hit that next node if it's safe in your rifle.
While I disagree that speed is the best indicator of over preasure I do believe a chrono is a must have tool for reloading.   Advanced reloading is not for everyone.....

[Jonathan_S]

My point is that a beginner with a 20-22” barrel shouldn’t be referencing book velocity taken with 26” custom barrels. And yeah ackley cases hide pressure signs but reloading ackley cases isn’t exactly beginner reloading

[yorketransport]

My point is that a beginner with a 20-22” barrel shouldn’t be referencing book velocity taken with 26” custom barrels. And yeah ackley cases hide pressure signs but reloading ackley cases isn’t exactly beginner reloading

That's the most important part right there. Just because you don't see the pressure doesn't mean it's not there.

Remember that max PSI specs have a lot to do with what the brass is rated to handle and not necessarily the firearm. Every manufacturer has a slightly different max yield strength which they'll use in their case head. One manufacturer's case may show traditional pressure signs at 120% of listed max PSI for the round while another may not show similar signs until 140% max PSI. This is why people will say that Hornady brass is "soft" or Lapua brass is "hard". If you load 120% max PSI in a Hornady case you may end up with ejector marks and a visibly flattened case head. The same 120% load in a Lapua case may not show the same signs, but it's still a 20% overload.

I don't have a problem with folks loading up beyond published max loads as long as they know what they're doing. I've spent a lot of time walking the line between over the top and reckless while working with a couple of wildcats. I've never damaged a gun or myself though because I'm very aware of actual pressure signs beyond primers and bolt lift. There's always a smarter way to do a stupid thing.

[Jolten]

My point is that a beginner with a 20-22” barrel shouldn’t be referencing book velocity taken with 26” custom barrels. And yeah ackley cases hide pressure signs but reloading ackley cases isn’t exactly beginner reloading

That's the most important part right there. Just because you don't see the pressure doesn't mean it's not there.

Remember that max PSI specs have a lot to do with what the brass is rated to handle and not necessarily the firearm. Every manufacturer has a slightly different max yield strength which they'll use in their case head. One manufacturer's case may show traditional pressure signs at 120% of listed max PSI for the round while another may not show similar signs until 140% max PSI. This is why people will say that Hornady brass is "soft" or Lapua brass is "hard". If you load 120% max PSI in a Hornady case you may end up with ejector marks and a visibly flattened case head. The same 120% load in a Lapua case may not show the same signs, but it's still a 20% overload.

I don't have a problem with folks loading up beyond published max loads as long as they know what they're doing. I've spent a lot of time walking the line between over the top and reckless while working with a couple of wildcats. I've never damaged a gun or myself though because I'm very aware of actual pressure signs beyond primers and bolt lift. There's always a smarter way to do a stupid thing.

Which is why as a newbie I reached out to experts.

If I ever get around to having a badger build I'd love to have a learning session with you and bigger hammer

[hunterofelk]

I get great results with 165 gamekings with Reloader 15 in my Rem M700, 22 inch barrel.

[Magnum_Willys]

I like Quickload just to confirm where I'm at pressure-wise.  You do have to input ALL your variables to get meaningful data including bullet speed and case volume, coal, etc and tweak powder burn rate to match but once all that is done it gives you a good idea of where you can nudge a load without being stupid.