Load formulas - starting in the middle?

[hounddawg]

I always and I do mean always start at minimum.

I used online Hogdon load info once for my .260 Rem and the first shot starting at the minimum load had a primer back out and the velocity was up there in the 6.5 284 range. Packed the rifle up, came home and double checked the load info. Did some more research and Hogdon had the .260 using 3.0 gns over the same powder and bullet for a 6.5 CM. For those not familiar with those two cartridges they have almost identical case volumes.

I pulled the remaining bullets and reloaded using the 6.5 CM data and life was good. If I had started in the middle or the top of that published load there is no doubt I would have blown that rifle up

 

[Bart B.]

I always and I do mean always start at minimum.

I used online Hogdon load info once for my .260 Rem and the first shot starting at the minimum load had a primer back out and the velocity was up there in the 6.5 284 range.

Primers backed out a few thousandths typically indicate low pressure because there's not enough to fully expand the case pressing its head against the bolt face to push it in flush with the case head.

Typically starts happening at charge weights about 10 to 15 percent below maximum.

 

[hounddawg]

Primers backed out a few thousandths typically indicate low pressure because there's not enough to fully expand the case pressing its head against the bolt face to push it in flush with the case head.

Typically starts happening at charge weights about 10 to 15 percent below maximum.

Tell you what Bart go get a .260 rem and use the H4350 recipe , start with max charge and when you get out of the hospital tell me tell me what happened

or

go to the Hogdon site and compare the load data for 142 SMK's for .260 Rem and 6.5 CM using H4350 then look at the same bullet using Varget and use some common sense

 

[reynolds357]

Tell you what Bart go get a .260 rem and use the H4350 recipe , start with max charge and when you get out of the hospital tell me tell me what happened

or

go to the Hogdon site and compare the load data for 142 SMK's for .260 Rem and 6.5 CM using H4350 then look at the same bullet using Varget and use some common sense

It looks like a reasonable load to me at the proper seat depth.

 

[hounddawg]

It looks like a reasonable load to me at the proper seat depth.

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

 

[reynolds357]

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]

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]

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]

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.