Pressure signs/chronographing

[glassman]

280rem,
I respect your way of doing your loading and I am sure the way you do it works good for you and that is the main thing.

But as this thread started out, about knowing your velocity will determine your MAX load, well, I am still in disagreement on this part.

Many thousands of reloaders have loaded for years and have found the "max" load for their guns with out ever using the chronograph.
I haven't used my chronograph in many years now and I have found the "max" load on many of my rifles, plus some for friends, with out using one.
Sure, I may not know what the Velocity is, but I sure know what the max load is!
When you have the "max" load, then it isn't going to matter what the velocity is, unless you need the figures for looooong range shooting

Head Space is the first thing I am checking, second is miking the case above the head, 3rd is the primer.

Here is case in point:
Speer Mag Tip bullet, it will give less velocity, with higher pressures, than say, a Speer SP, with the same given powder charge.

Oh...one more thing, just for info, in my Hodgdon manual, the 140 gr 280 has a load of 58gr of RL 19 for max...no bullet style given tho.

Happy Hunting.

 

[.280Rem]

280rem,
I respect your way of doing your loading and I am sure the way you do it works good for you and that is the main thing.

But as this thread started out, about knowing your velocity will determine your MAX load, well, I am still in disagreement on this part.

Many thousands of reloaders have loaded for years and have found the "max" load for their guns with out ever using the chronograph.
I haven't used my chronograph in many years now and I have found the "max" load on many of my rifles, plus some for friends, with out using one.
Sure, I may not know what the Velocity is, but I sure know what the max load is!
When you have the "max" load, then it isn't going to matter what the velocity is, unless you need the figures for looooong range shooting

Head Space is the first thing I am checking, second is miking the case above the head, 3rd is the primer.

Here is case in point:
Speer Mag Tip bullet, it will give less velocity, with higher pressures, than say, a Speer SP, with the same given powder charge.

Oh...one more thing, just for info, in my Hodgdon manual, the 140 gr 280 has a load of 58gr of RL 19 for max...no bullet style given tho.

Happy Hunting.

It's the way my father loaded and taught me to. Between the two of us, it's worked for 40 plus years. The worst pressure problem he ever had was popping a primer or two. And I litterally mean a couple of times. Myself, I've never had to hammer a bolt open, blown a primer, etc. I have at times loaded warm loads that cratered primers, or left a little shiny mark on the case head. I backed off.

I want to be clear here. I dont know my pressures, and never suggested that. I said that the chronograph is one tool I use to indicate where I am pressure-wise in relation to the data I'm using. I'm using the data at hand and my experience to make a best guess based on all the information.

I have to ask how you know your max loads? Are you saying just stopped at a certain point you though safe and called it max, or are you saying you know it's a max pressure or velocity load? Do you keep adding powder until you see pressure signs then back off, or what? Or do you simply use the "max powder charge" from the book? From "miking" the casehead, checking head space, and looking at the primer? I've heard and read that "miking" can be very unreliable because you have to measure in EXACTLY the same spot each time, and most micrometers aren't THAT accurate at those 0.001 levels. But like you said, if it works for you. It is reliable IF you have the equipment and ability to do it correctly, or so I've heard and read.

Im curious why Hodgdon would be giving data for Alliant's R-19 powder? Also, some Speer data I found online not too long ago, listed 59grs of R-19 with the 140 Grand Slam at 3040fps. I originally worked up my load from the Hornady manual listing 57.4grs of R-19 at over 3000fps as max for the 139. Also, I load the .280 over all published data because the SAAMI max is 60Kpsi because the original chambering for the .280 was in an auto loader...it can safely be loaded to .270 pressures of 65Kpsi. The .280 is the only round I'll exceed book max velocity with. If a .270 can drive a 130 at 3150, a 135 at 3050, or a 140 at 3000 with published data, there's no reason in the world I can do that at least, and slightly better actually with the .280's ever so slightly larger bore. Alliant lists a load running a 150 at 3000fps in the .270 on its website. For the .280Rem Nosler lists 57grs of R-19 at 3150 with 140s in a 26" bbl. If you look at this .270 data here: Real Guns - Handload Data - .270 Winchester there's no reason a .280 can't give similar performance with similar wt bullets, if not better.

And like you said, it works for me. Has for a while.

 

[glassman]

280,
Your question:
I have to ask how you know your max loads? Are you saying just stopped at a certain point you though safe and called it max, or are you saying you know it's a max pressure or velocity load?
When the bolt starts to get tight, that's the one main indicator. But of course there are other things too. I also use a RCBS Precision Mic to check the headspace.

Do you keep adding powder until you see pressure signs then back off, or what?
That is correct? That's exactly how I've done it for 34 yrs now. I would imagine that is pretty much how most people have done it to, especially if they don't have a chronograph.

do you simply use the "max powder charge" from the book?
I use it only for a guide. The 'max" charge in one manual is only a guide and nothing more, the next manual maybe total different. Check this load out and see what you come up with, see what the manuals say:
7mm Mag
160 Speer
65 gr of H4831
(this is what I have loaded for over 25 years in my rifle, plus in 3 other 700 models - but it's over max in most of the manuals that I've seen).

When I start a new lot of powder, I always start low and work up again. Then when I start seeing the pressure signs again I stop. If I should happen to reach a "max" load of 1.5 grs less than before, well, then that is where I would have to stop, for I am at the "max" pressure for that "lot" of powder, so it won't matter what my velocity is, especially if it is on the low side, because I am at 'max".

Happy hunting & keep safe....

 

[.280Rem]

280,
Your question:
I have to ask how you know your max loads? Are you saying just stopped at a certain point you though safe and called it max, or are you saying you know it's a max pressure or velocity load?
When the bolt starts to get tight, that's the one main indicator. But of course there are other things too. I also use a RCBS Precision Mic to check the headspace.

Do you keep adding powder until you see pressure signs then back off, or what?
That is correct? That's exactly how I've done it for 34 yrs now. I would imagine that is pretty much how most people have done it to, especially if they don't have a chronograph.

do you simply use the "max powder charge" from the book?
I use it only for a guide. The 'max" charge in one manual is only a guide and nothing more, the next manual maybe total different. Check this load out and see what you come up with, see what the manuals say:
7mm Mag
160 Speer
65 gr of H4831
(this is what I have loaded for over 25 years in my rifle, plus in 3 other 700 models - but it's over max in most of the manuals that I've seen).

When I start a new lot of powder, I always start low and work up again. Then when I start seeing the pressure signs again I stop. If I should happen to reach a "max" load of 1.5 grs less than before, well, then that is where I would have to stop, for I am at the "max" pressure for that "lot" of powder, so it won't matter what my velocity is, especially if it is on the low side, because I am at 'max".

Happy hunting & keep safe....

I would submit to you that loading until you get pressure signs is somewhat dangerous. But, it's worked for you. Originally, my father did that, and that was a way I learned, but learned that the chronograph, though it's not fool proof, will most often tell me I'm at max before I see signs of stiff bolt lift or on the brass. The way I approach it, I almost never get pressure signs. Not saying never, but rarely. As for your 7mmRM load, since I run 66grs of R-22 with a Nosler Accubond (which I think is Nosler's max powder charge) at 3080fps in a 25.6" bbl, I'd bet your load isn't too hot and running around 3000-3075fps in a 24"-26"bbl, which is what is doable safely in the 7mmRM.

 

[jwp475]

A squared action with the luggs lapped will exceed SAAMI pressures considerable before the bolt get sticky if at all...

 

[overbore]

.280

Son, Since my grandson is now an experienced hand loader, and since I have a box of reloads dated 1958, be assured that I use that term with respect and some level of experience.
First point: Hogdon manual and most other published max loads have decreased over the long term from legal concerns. A 4895 1970 max load is not the same as a 2008 max load.
#2 The specific data source for OCW load is Practical Riflery Forums... techniques and equipment of the practical rifleman... :: Index
#3 I have published a primer intensity article based upon actual pressure measurements done by another; have you studied it?
#4, With respect, do you start with computer load program or programs to see if your proposed load has an associated pressure number or warning?

As a general purpose or mission statement,I view these posts as intended to move the knowledge and safety of our sport along. I have nothing left to prove or sell yet the oldest of us think we will still be learning when the lid on the coffin goes shut. Cordially, Overbore

 

[Boss Hoss]

Son, Since my grandson is now an experienced hand loader, and since I have a box of reloads dated 1958, be assured that I use that term with respect and some level of experience.
First point: Hogdon manual and most other published max loads have decreased over the long term from legal concerns. A 4895 1970 max load is not the same as a 2008 max load.
#2 The specific data source for OCW load is Practical Riflery Forums... techniques and equipment of the practical rifleman... :: Index
#3 I have published a primer intensity article based upon actual pressure measurements done by another; have you studied it?
#4, With respect, do you start with computer load program or programs to see if your proposed load has an associated pressure number or warning?

As a general purpose or mission statement,I view these posts as intended to move the knowledge and safety of our sport along. I have nothing left to prove or sell yet the oldest of us think we will still be learning when the lid on the coffin goes shut. Cordially, Overbore

I must say very well put sir.

 

[.280Rem]

Son, Since my grandson is now an experienced hand loader, and since I have a box of reloads dated 1958, be assured that I use that term with respect and some level of experience.
First point: Hogdon manual and most other published max loads have decreased over the long term from legal concerns. A 4895 1970 max load is not the same as a 2008 max load.
#2 The specific data source for OCW load is Practical Riflery Forums... techniques and equipment of the practical rifleman... :: Index
#3 I have published a primer intensity article based upon actual pressure measurements done by another; have you studied it?
#4, With respect, do you start with computer load program or programs to see if your proposed load has an associated pressure number or warning?

As a general purpose or mission statement,I view these posts as intended to move the knowledge and safety of our sport along. I have nothing left to prove or sell yet the oldest of us think we will still be learning when the lid on the coffin goes shut. Cordially, Overbore

My load work up is simple. I check 2-3 sources. For instance, If loading for my .280, I'd look at say Nosler and Hornady. Both give very similar data for R-19 and their respective 139/140gr bullets. 57 max for Nosler at 3150 from a 26" bbl, and 57.4 for Hornady at a little over 3000 in a 24" bbl. I figure knocking off about 50-75fps from Nolsers velocity for my expectations for R-19 and 140 grain bullets because I'm shooting 24" bbl. I start a few grains under max for the given powder/bullet combo. I start at about 54 grains, and check accuracy and velocity. Supposing it's under the listed velocity given of around 3050 for the top end loads in the books, I work up. If my 54gr load is 2500fps, I may add 2 grains...if its 2850, I'll work up a grain at a time until my velocity is in the 3050-3075 range, and call it good if the accuracy is there. If not, then I try another bullet or powder and start over. Add to that now that I check Quickload, and it predicts I should be in safe pressure ranges with my loads, plus the fact that I see no outward signs of pressure and brass life is good over the last 20 years, I figure I'm good to go, even though I'm using 1 more more grain of powder than the book says is max. Differing lots of powder can account for that difference. If I change anything...brass, primer, etc, I back off about 3 grains an start over. Thats an example of how I'd work up a load.

 

[jwp475]

Son, Since my grandson is now an experienced hand loader, and since I have a box of reloads dated 1958, be assured that I use that term with respect and some level of experience.
First point: Hogdon manual and most other published max loads have decreased over the long term from legal concerns. A 4895 1970 max load is not the same as a 2008 max load.

Pressure testing equipment is better today and more accurate, than in 1958. Reloading manuels in the late 50'searly 60's show many loads that were over SAAMI max.

 

[.280Rem]

My load work up is simple. I check 2-3 sources. For instance, If loading for my .280, I'd look at say Nosler and Hornady. Both give very similar data for R-19 and their respective 139/140gr bullets. 57 max for Nosler at 3150 from a 26" bbl, and 57.4 for Hornady at a little over 3000 in a 24" bbl. I figure knocking off about 50-75fps from Nolsers velocity for my expectations for R-19 and 140 grain bullets because I'm shooting 24" bbl. I start a few grains under max for the given powder/bullet combo. I start at about 54 grains, and check accuracy and velocity. Supposing it's under the listed velocity given of around 3050 for the top end loads in the books, I work up. If my 54gr load is 2500fps, I may add 2 grains...if its 2850, I'll work up a grain at a time until my velocity is in the 3050-3075 range, and call it good if the accuracy is there. If not, then I try another bullet or powder and start over. Add to that now that I check Quickload, and it predicts I should be in safe pressure ranges with my loads, plus the fact that I see no outward signs of pressure and brass life is good over the last 20 years, I figure I'm good to go, even though I'm using 1 more more grain of powder than the book says is max. Differing lots of powder can account for that difference. If I change anything...brass, primer, etc, I back off about 3 grains an start over. Thats an example of how I'd work up a load.

I will further address my "velocity indicates pressure" by saying that if my starting load above of 54grs showed a velocity of 3000fps, then I would not say "Hey I got a fast gun" and continue to work up to the "book max powder charge" because the book says that's a safe max load. I would have in fact started at my gun's max load, though inadvertently.

Also, I have read some things on primers and their effect on pressure/velocity. The consensus seems to be there is nothing that is scientifically predictable about it. The effect primer change can have is dependant on many other factors such as load density, powder burn rate, case capacity, bullet wt. etc. Now in any particular application you might could find a trend with regard to primer's effect on velocity/pressure, but the rules will be different for a .44mag using Unique with cast bullets, and a .300WinMag with R-22 and 180gr Copper jacketed bullets. A hotter primer giving less velocity with higher pressure, and a "cooler" primer giving more velocity and less pressure, and vice versa to both have all been observed.

overbore,

I would love to read what you said you wrote about primers. Is it online? Or where can I find it?

 

[308sako]

The law of diminishing returns

When you keep adding powder and velocity does not go up at the same rate it has... pressure and not performance is happening. Let's say you get 50 ft/sec's for each half grain, then you add a 1/2 and only get 35 and another 1/2 yields 23 ft/secs... That powders burning rate is peaking and may not be the correct choice for your application.

 

[eddybo]

Hey .280 about primers? Do you recon that the differences seen could be attributed to other factors than the primers themselves? Like for instrance I have seen primers that will break neck tension and actually push the bullet into the lands. I have also seen primers that would not even budge a bullet. I have heard that a projectile actually stops during the process. Do you think that maybe it isnt the strength of the primer but what they do to the projectile?

 

[.280Rem]

Hey .280 about primers? Do you recon that the differences seen could be attributed to other factors than the primers themselves? Like for instrance I have seen primers that will break neck tension and actually push the bullet into the lands. I have also seen primers that would not even budge a bullet. I have heard that a projectile actually stops during the process. Do you think that maybe it isnt the strength of the primer but what they do to the projectile?

Generally speaking, yes primers can affect pressures with little gain in velocity. But, most problems in reloading can be headed off by working up your loads as recommended. Changing primers under the same powder charge and bullet you've been shooting can cause a problem, depending on the other factors.

In fact primers and their effect are largely un predictable. In some cases a hotter primer can lower velocity, and raise pressure, and a cooler primer vice versa. The key to it all is working up the load with components remaining the same, and watching your velocity, then your brass.

Recently read a post on another site where a guy was loading for the 30-06 with 180s and H4350. Said he hit @ 2730fps some 2.5 grains below "book max". He's started 6.5 grains under max at 2550, and jumped 2 grains of powder and nearly 200fps to the 2730 level with the first and second batch. But since the book said he could add 2.5 more grains, he added 2 more, and got a chrony reading of 2900 fps, and a VERY sticky bolt and extraction with a 180 in a 30-06! I told him that had I been watching the chrony, I'd have stopped at the second loading due to the velocity. And that just goes to show you how worthless a "book max" powder charge is to safety. Had he gone ahead and loaded to "book max" he may have damaged his gun, or worse! The chronograph is your friend IF you use it correctly.