Load formulas - starting in the middle?

[reynolds357]

Originally Posted by hounddawg

being kind I would say you either have not researched it or like to live dangerously

Hogdon load data for H4350 and 142 SMK's

6.5 x 55 - case capacity 57.9 gns of H2O - 39.0 to 43.0
.260 Rem - case capacity 53.5 gns of H2O - 41.5 to 44.5
6.5 CM - case capacity 52.5 gns of H2O - 38.0 to 41.5

case capacity can vary slightly, case data obtained from

https://www.chuckhawks.com/case_capacity_matters.html

it was a lesson learned for me. Never trust a single source of load data, even from a powder or bullet manufacturer and always start at the lowest charge

ended up maxxing at 41.1 and 2800 FPS from a 30 inch Shilen

Looks perfectly reasonable, even though Sierra shows max under that starting load. Throw out the 6.5x55 because it is a low pressure load.
Hodgdon has a lot of hot loads. I have also been told they have the best pressure testing equipment.

[hounddawg]

well I have been shooting the .260 Rem for 8 or 9 years now and even with a 30 inch barrel I consider 2800 FPS a hot load. In comparison Hogdon lists 46.0 gn max of H4350 and 2735 FPS for a 6.5 284 with a 24 inch barrel. 6.5 284's case capacity is appx 68 gn of H2O.

Still it is a free country and people can do as they please, it is their eyes, hands and rifles they are risking. I just hope they are a few benches down from me


edit

Oh and if working up a load for a .260 with that bullet and powder combo the usual disclaimer about starting lower and working your way up. Just becasue it works in my rifle does not mean it will work in yours and for God's sake do not trust the Hogdon data for that particular combo. It is just plain dangerous

[reynolds357]

Hounddawg. I am being sarcastic.

[44 AMP]

Having said that, for a bolt rifle 99% of the time, I jump in at max. I find it odd that for reloading we must assume that all rifles behave differently. There is some truth to that, but Its odd that the factory loads are now run up at max pressures and we dont see all these rifles that behave differently blowing up. There is some super hot factory ammo out there now. I have not heard of anything getting blown up.

Is this intended as sarcasm? IF so, you REALLY should use the smilies, or state its sarcasm.

If you're being serious, you are in error on several points.

[hounddawg]

I am a pretty easy going guy with what the wife says is a twisted sense of humor. However I don't joke around on a subject that could easily get someone seriously injured or killed.

[Unclenick]

Yep. Smiles are needed for sarcasm. Almost nobody on the board is a professional writer, adept at communicating tone and sense of humor, so what looks like a funny to the author can often be taken seriously, especially by newbies who are most at risk of believing it and thereby being lead to try something foolish.

[reynolds357]

That post was serious. The h4350 load being reasonable was the sarcastic post.
I honestly dont see an error there on any point. Some of the factory ammo is pushing the pressure envelope. If these drastic differences in bores indeed exist, then the factories are running a risk as high as the reloader would run. I can name you three lines of ammo that are on the ragged edge of the envelope. A couple of lots had to be dialed back because they were over SAAMI max in the test rifle. It was told me by someone in the industry that he once tested some premium ammo that was north of 80kpsi.

[reynolds357]

Originally Posted by hounddawg

I am a pretty easy going guy with what the wife says is a twisted sense of humor. However I don't joke around on a subject that could easily get someone seriously injured or killed.

Which does bring up a point. Though the load looks excessive by all other available data, why has Hodgdon not revised it? They do have the better pressure testing ewuipment.

[Unclenick]

The pressure test barrel is built to SAAMI standard. The ballistic technician signs off on the test results and they are what they are. Speer said the same thing about the load that was popping the Handi Rifle when the owner reported it. They had data on file that proved that data was safe so their backsides were covered and their lawyers were happy. If they admit a mistake and change something, that give a suing lawyer ammunition to say they knew they had done something wrong. So a hot load won't easily change, and that, ironically, is for liability reasons.

But in addition to that, there really are variations in some guns. I can buy .3065 groove Palma barrels for .308. There, the objective is squeezing every last foot per second out of the gun to keep the bullets supersonic to the target.

I've also run into a fellow who had a rifle that apparently had a roughing reamer run into the chamber but no finishing reamer so he had no proper throat. Some light bullet ammo would still fit in it, but as you can guess, longer bullet ammo was jamming the lands, and that typically raises peak pressure about 20%. Short chambers and throats can happen, and guns get sent back for factory service for it. Unlike Europe, there is no law requiring each gun to be proofed or even test-fired by the factory and not all are.

As to who is loading what ammo to what pressure, unless you have instrumentation, you can only speculate about what peak pressures you are actually getting. Feeling "hot" and having high velocity don't tell you that your peak pressure was high; only that you had enough ejecta mass and muzzle pressure to produce high recoil energy and high enough average pressure over the whole bore length to produce high bullet KE. Note, for example, that NATO and the CIP both use SS109/M855 pressures for 5.56 and 223 Rem, respectively, but you can buy ammo loaded to the same velocities without going over the 6% lower SAAMI pressure limit from IMI and Winchester. It's just a matter of getting enough of a slower powder in the case to do the work. The recoil will actually feel a little heavier using that approach, even though peak pressure is lower.

There is also odd stuff that happens. We had a fellow on another forum who ran ammunition testing for government agencies for a couple of years. He said that by the time you've fired a quarter of a million rounds of commercial ammunition, you've usually seen every kind of load error a handloader can dream up, like overloaded rounds (this is the stuff recalls are made of), uncharged cases, backward seated primers, and a few the handloader does encounter with fired brass, like missing flash holes, or ones that a handloader would normally notice during loading, like bullet jackets with no lead core in them.

Stuff happens in mass-manufacturing. I see no point in taking even a small risk of getting hurt by it if a few simple and prudent steps will prevent that.

[44 AMP]

Having said that, for a bolt rifle 99% of the time, I jump in at max. I find it odd that for reloading we must assume that all rifles behave differently. There is some truth to that, but Its odd that the factory loads are now run up at max pressures and we dont see all these rifles that behave differently blowing up. There is some super hot factory ammo out there now. I have not heard of anything getting blown up.

I honestly dont see an error there on any point. Some of the factory ammo is pushing the pressure envelope. If these drastic differences in bores indeed exist, then the factories are running a risk as high as the reloader would run. I can name you three lines of ammo that are on the ragged edge of the envelope. A couple of lots had to be dialed back because they were over SAAMI max in the test rifle. It was told me by someone in the industry that he once tested some premium ammo that was north of 80kpsi.

First point, the "pressure envelope" isn't what you imply it is. SAAMI specs are an industry working limit, NOT a safety boundary. They are an agreed upon limit, intended to be safe in every "modern firearm in good condition" out there. Under normal conditions they are well below the danger point

Next point, certain lots of factory ammo needing to be "dialed back" to meet SAAMI specs is only proof that errors can and do happen. Did any of the "too hot" stuff get sold to the public??

Next point, rifles (all guns, actually) DO behave differently. Nearly all the time the difference is small, often its not even noticeable without careful checking. BUT, there are times when the difference is large. UNTIL you know for certain that isn't going to happen, being prudent (starting with starting loads) is the smart way to go.

You can start at max, its your gun and your choice, and you maybe get away with doing that your whole life. Doesn't mean its the smart thing to do.
Modern bolt actions are the most forgiving about pressures and can give the impression that all guns are like that, and that starting at max is ok, because YOU never had a problem in your rifles.

Unless they are already defective, guns don't blow up if you happen to put a toe over the SAAMI line. Remember SAAMI specs are for WORKING PRESSURE, not blow up limits. Being over SAAMI can cause problems, but you don't hear about the rifles blowing up, because they don't blow up.

Lots and lots of problems short of blowing up simply don't get on the internet . Doesn't mean there's no problem. Just means its not being reported on the net.

[hounddawg]

Which does bring up a point. Though the load looks excessive by all other available data, why has Hodgdon not revised it? They do have the better pressure testing ewuipment.

heck if I know I emailed them about it two years ago. If you want to doubt me by all means buy a cheap used .260 and see how high you can go with that bullet and powder. I have no reason to lie and my chrono records to back up what I posted. Hogdon has max velocity at 2735 @ 44.5 gns so absolutely nothing about that load data makes sense

here is the spreadsheet with the initial tests (part 2) like I said part 1 got canceled at round 2 loaded to 41.8 gns on part 1 as soon as I saw my velocities and that backed out primer. Check the velocities out compared to Kilotankers 6.5 CM using 140 gn bullets and H4350. Generaly the 6.5 CM will get a few more FPS than a Rem .260 using the same load becasue of the improved shoulder angle on the Creedmoor. My Chrono data is good, Hogdon's load data for this bullet/powder is not

[reynolds357]

Originally Posted by 44 AMP

First point, the "pressure envelope" isn't what you imply it is. SAAMI specs are an industry working limit, NOT a safety boundary. They are an agreed upon limit, intended to be safe in every "modern firearm in good condition" out there. Under normal conditions they are well below the danger point

Next point, certain lots of factory ammo needing to be "dialed back" to meet SAAMI specs is only proof that errors can and do happen. Did any of the "too hot" stuff get sold to the public??

Next point, rifles (all guns, actually) DO behave differently. Nearly all the time the difference is small, often its not even noticeable without careful checking. BUT, there are times when the difference is large. UNTIL you know for certain that isn't going to happen, being prudent (starting with starting loads) is the smart way to go.

You can start at max, its your gun and your choice, and you maybe get away with doing that your whole life. Doesn't mean its the smart thing to do.
Modern bolt actions are the most forgiving about pressures and can give the impression that all guns are like that, and that starting at max is ok, because YOU never had a problem in your rifles.

Unless they are already defective, guns don't blow up if you happen to put a toe over the SAAMI line. Remember SAAMI specs are for WORKING PRESSURE, not blow up limits. Being over SAAMI can cause problems, but you don't hear about the rifles blowing up, because they don't blow up.

Lots and lots of problems short of blowing up simply don't get on the internet . Doesn't mean there's no problem. Just means its not being reported on the net.

That ammo had been sold for years with that gross over pressure before it was discovered.

[reynolds357]

Originally Posted by hounddawg

heck if I know I emailed them about it two years ago. If you want to doubt me by all means buy a cheap used .260 and see how high you can go with that bullet and powder. I have no reason to lie and my chrono records to back up what I posted. Hogdon has max velocity at 2735 @ 44.5 gns so absolutely nothing about that load data makes sense

here is the spreadsheet with the initial tests (part 2) like I said part 1 got canceled at round 2 loaded to 41.8 gns on part 1 as soon as I saw my velocities and that backed out primer. Check the velocities out compared to Kilotankers 6.5 CM using 140 gn bullets and H4350. Generaly the 6.5 CM will get a few more FPS than a Rem .260 using the same load becasue of the improved shoulder angle on the Creedmoor. My Chrono data is good, Hogdon's load data for this bullet/powder is not

I already told you I agree with you. I also wonder why Hodgdon tests that load as safe. I honestly dont think it would blow up a bolt action.

[mpmo]

Thanks for all the feedback! Got my next batch done. Started at the bottom and added .2gr for 3 additional rounds (well under max.) Will be testing this weekend.

[44 AMP]

That ammo had been sold for years with that gross over pressure before it was discovered.

What ammo would that be??

Seem to me that any ammo used by the public that is dangerously over pressure would make itself known in fairly short order.

Being over the "speed limit" regulation and being dangerous are not automatically the same thing.

[ghbucky]

Thanks for all the feedback! Got my next batch done. Started at the bottom and added .2gr for 3 additional rounds (well under max.) Will be testing this weekend.

Have fun! Making your own ammo added a whole new level of fun to shooting games for me.

[mpmo]

Ok. Results are in. No overpressure in either handgun. A bit more PF that what I'm looking for, even at the minimum recommended powder levels. Got a few more questions about where to go from here.

1.PF for 125gr Sierra FMJ RN at lowest grain was still average 135 in one gun and 130 in the other. No feed or cycling issues. Can I go below the recommended starting grains now to try to get closer to 125?

2.I noticed less velocity on the first round fired pretty much everytime I started with a new test. More so with the cold barrel. Should I throw this data out? Why would this occur.?

[Aguila Blanca]

Originally Posted by momo

1.PF for 125gr Sierra FMJ RN at lowest grain was still average 135 in one gun and 130 in the other. No feed or cycling issues. Can I go below the recommended starting grains now to try to get closer to 125?

What was your minimum velocity and power factor? What was your extreme spread ... and how many rounds did you run through the chronograph?

It must have been in one of your other threads where I quoted the IDPA rule book on how they test ammo for power factor. This is the protocol for larger matches, like regionals; I don't know if any clubs bother at their regular competitions, but you might as well have ammo that you know will always pass if you happen to shoot a big match.

You show up ... they pull three rounds at random from your ammo box/bag and shoot them over the chronograph through your gun. Two of the three must make the minimum power factor. That means, depending on the extreme spread, an average of 130 or 135 might not be good enough because you can't count on the random pick getting rounds that are near the middle or high end of the pack.

For this purpose, I want to know that the worst round will make power factor, and then try to minimize my extreme spread so that the faster ones aren't a whole lot faster. If you'll be alternating guns for competition, you also want to be sure that your worst round will make power factor in the slower gun.

What were the slowest velocities you recorded in this round of testing?

[mpmo]

Originally Posted by Aguila Blanca

What was your minimum velocity and power factor? What was your extreme spread ... and how many rounds did you run through the chronograph?

What were the slowest velocities you recorded in this round of testing?

Bullets are in short supply and I just wanted to get some data for a starting point so I just loaded 4 rounds (2 rounds per gun.) at each of the powder levels. So obviously, it's not going to be good enough. But once I get in the proper range, I can load more which will show a better average. That being said. Also, I assume with these results and assumed going in, I will have a different formula for each of the guns.

At lowest powder level loaded (book spec minimum):
Gun 1: 129-131PF, 1034-1049fps
Gun 2: 133-137PF, 1060-1097fps

I'm not too concerned right now about making exact power factor. I doubt they will be testing rounds at the local level matches I'm going to attend. And the league I shoot in doesn't have any PF restrictions. But I want to be pretty close. I'm going to shoot for 126-128. I'm sure if I ever made a regional match, I will have to change some things.