working up loads / chronographs & velocity

[Major Beer]

reloading manuals advise starting 10% below max and working up. is this when a chronograph is needed or do you trust your scale? while working up loads, should velocities be checked and compared to your powder loads as a check against your scales? just curious on how to safely achieve the higher powder contents of my loads - right now i am about 5% under max and feel a little hesitant about working up any higher.

 

[30Cal]

When your chronograph tells you that you are at the velocity listed for Max loads, then you stop going up in powder charge.

It's not that your scales are necessarily wrong--they may be right on. The problem that comes in is that the burn rate for a given powder will vary from lot to lot. Your barrel is going to be different than the manufacturers test setup as well. There are several ways to exceed maximums if you aren't watching velocity.

Ty

 

[halvey]

What caliber, powder, etc are you loading?

When I first started reloading I made and shot a lot of light loads. I wouldn't push it just starting out without a chrono.

 

[USSR]

reloading manuals advise starting 10% below max and working up. is this when a chronograph is needed or do you trust your scale? while working up loads, should velocities be checked and compared to your powder loads as a check against your scales? just curious on how to safely achieve the higher powder contents of my loads - right now i am about 5% under max and feel a little hesitant about working up any higher.

Major,

Reloading manuals are simply a guide to producing ammo that is safe to shoot in all guns under all circumstances, and the velocities produced using their loads in their guns will not be the same in your gun. The loads that are listed are vetted by the reloading manual's lawyers, and the maximum loads listed are in no way actually maximum loads generating SAAMI maximum pressure. That being said, do start at the recommended 10% below max and work your way up. Now, what you need to do is basically two things: 1. Obtain a chronograph, use it, and have an understanding of the velocity range that is safely obtainable using your load in a typical rifle (and it is generally higher than you will find listed in reloading manuals). 2. Learn how to read pressure signs on fired cases. By using these two tools in conjunction with each other, you will produce safe, accurate, and enhanced performance ammunition.

Don

 

[pcf]

Dropping your load 10% for starters is not a good rule of thumb. Dropping a maximum charge of W296 or H110 by 10% in a 44 mag, is going to leave you with very inconsistent performance. Also, in high volume cases with small charges of fast burning powders dropping you powder charge too much can result in high and unsafe pressures, or squib loads, hangfires and misfires. Your starting load may only be 3-4% below maximum.

Trying to determine a safe pressure by using a chronograph, is the equivalent to guessing a cars horse power based on how fast gas leave the exhaust. It doesn't make any sense.

Even if your firearm is the exact same one used by the publisher of load data and your velocity is not the same it doesn't mean that you loads are generating different amounts of pressure. The are umpteen different factors in a firearm that cause the velocity to vary from other "identical" firearms.

Do not go out of the bounds of published data if your not willing to accept the risk. Work your loads up from a safe minimum load and watch for pressure signs. Chronographs have there place in load development, but they do not measure pressure levels. If your current load doesn't meet your velocity expectations, try a different powder or bullet, etc.

 

[Ol` Joe]

The loads that are listed are vetted by the reloading manual's lawyers, and the maximum loads listed are in no way actually maximum loads generating SAAMI maximum pressure.

USSR I hate to differ but this has been discussed before in a number of forums. The books give what SHOULD BE safe starting point and tell you what they found to be the safe stopping point in THEIR GUN.

The manufactures test with their components, in their lab, and under their conditions and report the results. No company wants to give wimpy loads as the max with their component when compared to another brand and they do run them up to the limit SAAMI lists as max. The loads may well not be at max SAAMI pressure in your gun, but it was in the test platform used to gather it.

I can`t remember where I saw it, but at one time I read that canister powders tolerances can vary up to 10% from lot to lot. This relates along with what ever the differance in our components to the variations we see in the manuals top loads. Everthing adds up in relation to the pressure developed by our loads.

Here`s a recent thread on old vs new manuals and their loads from a argument over on AR. There is some feed back there from the guy that use to be the head ballistician at Nosler. The thing switched gears after the first dozen posts but the facts do get posted.

http://forums.accuratereloading.com/groupee/forums/a/tpc/f/2511043/m/997104392/r/590104592#590104592

 

[dakotasin]

i agree w/ ussr on principle... the manuals are simply a guide. your rifle/chamber, your lot of powder, your seating depth, your bullet, etc are all factors that come into play that cannot possibly be predicted by a loading manual. all that aside, the concept is too advanced for the original poster to go playing in uncharted waters.

major beer- get ahold of a speer #13 manual. i have found that their loads are actually pretty close to max. in some cases their max load is the max for me, and in other cases, i find that i can go up a little. the sierra and nosler manuals provide decent references, but i find their data quite diluted.

get a chronograph, and use it along w/ looking for pressure signs on the case. the two used in conjunction are a major help. the chronograph will tell a story by itself about pressures and spot inconsistencies that you otherwise can't see. another sign is case life... if you're primer pockets are loose in one or two firings, then you are too hot... there's a lot that goes into getting into true performance, but 5% below listed max is not a walk on the wild side...

 

[USSR]

The loads may well not be at max SAAMI pressure in your gun, but it was in the test platform used to gather it.

Ol' Joe,

Feel free to disagree, but if you think that Sierra's published Max loads are running at SAAMI maximum pressures in there rifles, you are delusional. Do you think that for one moment their lawyers would allow a TRUE SAAMI maximum pressure load to be published in the off chance that someone uses it with perhaps a change in brass from a commercial case to a military case with reduced capacity, and has a catastrophic situation? No Way! Sierra's reloading manual is EXTREMELY conservative, and in a sue happy environment, who can blame them.

Don

 

[Major Beer]

thanks for the input - i have been my share of reading and had a strong feeling a chrono was in my future. my neighbor / shooting buddy and i got a Lee Anniv kit this Spring. it came with a basic balance scale - just to give you a quick info on our equipment.

i am loading 9mm with Hodgdon HP-38. I started out with the -10% rule. I have reloading (and shot) about 300 rounds and no case has shown any signs of stress. I have no plans of going above my current powder weight (-5%) until i buy a chronograph. i will follow this up by stating i am taking my sweet time, measuring cases, examining cases, etc and i have even gone so far to double check my grains by converting them to grams and weighing on a digital scale. i did this to make sure the scale was accurate - and it appears to be very accurate. my manual states to weigh your powder every 10 rounds, i have been checking the weight every five rounds. once i confirmed the Lee scale was accurate, i went back to checking them every 10.

I am fine with where i am at but i am looking into loading .223 in the near future. i would like to up my loads in the 9mm in the future as well - i just want to be safe. i get paid Friday - was planning on getting some new toys.

thanks guys - this forum has taught me a lot quick.

 

[dakotasin]

once you suddenly burst onto a performance epiphany, at first it is hard to believe that what you are doing is safe... i mean, can a load that produces that much recoil be safe? or a load that kicks so little that you can sometimes see the bullet in flight, depending on light levels - well, is that safe??? once you get into handloading, the world of cartridges and their performance levels takes on a whole new meaning. after you've done it for a bit, all these 'caliber wars' that erupt between folks using factory ammo becomes a bit laughable... once you no longer are bound by the constraints of factory garbage, then you can realize what a cartridge is truly capable of at both ends of the spectrum, and every point along the way.

next stop for you is a chronograph...

 

[Dave R]

No company wants to give wimpy loads as the max with their component when compared to another brand and they do run them up to the limit SAAMI lists as max.

I'm not sure that's true, either. I think some companies are more conservative than others. One genuine example: look at Hodgdon's reloading manual and Speer No. 13, for .380acp. The MAX load in Hodgdon's book is LESS than the STARTING load for Speer 13 for some powders.

That's why its smart to look at more than one manual. Of the manuals I've seen, Speer seems to have the "hottest" loads. In their description of several cartridges, they note that, when they changed test methodologies from copper crusher to transducer, they would up with significantly hotter loads. So that means even the teams that produce the manuals have imperfect pressure testing.

 

[pcf]

Major,
Your logic escapes me, you're not going to increase your powder charge until you buy a chronograph. Listed velocities does not directly correlate to pressure produced in your gun. Chamber and case dimension can have significant effect on chamber pressure but little effect on muzzle velocity. If you get a chronograph and your velocity is higher than listed it doesn't mean that your exceeding SAAMI maximum pressure. Likewise you may be well below the listed velocity for your load and be at or exceeding SAAMI maximum pressure. Look for pressure signs.
HP38 and W231 are the same powder, produced in the same Olin plant. You can use the data for the other with no risk.

 

[dakotasin]

pcf makes good points!

the thing w/ chrony testing is not to stop when you reach the published velocity, but to make sure that velocity jumps are predictable, and consistent.

eg, when you increase a load by .5 grains, and it comes back w/ an increase of 50 f/s, then you throw another half in, and it goes up 40 f/s, so you toss another half in and it runs up 35 f/s, and you throw another half in, and it goes up 125 f/s... well, you have reached pressure problems. the load is now unreliable, and unpredictable. that's where a chrony really shines...

ya gotta take into consideration all the many variables that go into it... some barrels are faster than others, some chambers are tighter... if you happen to have a fast barrel and a tight chamber, your velocity will be markedly higher than reloading manuals could be... so, even though you are right in between in the data, does that mean you should stop? or, does that mean you continue to monitor other pressure signs and keep trudging ahead, enjoying the extra performance??

 

[Major Beer]

is velocity a good constant?

first off - thanks for all you concern, and information. the guys from the chat room from Guntalk were right - lots of good stuff here.

i am not maxing any loads - just trying to make a something that works and is safe. my Hodgons manual confirms where i am at as far as safety - still have alot of room before i get near the max line. i started understanding the finer points from reading around this forum and started asking specifics. i was just wondering is velocity a good constant to guage your mix by?

1 - i am not upping and loads until i have a chrony (tomorrow?)

2 - i started at the -10% for my first 250, went to -5% for my last 50. all shot fine. not expansion of brass or noticable stress - i still have all my fingers too . all brass was from brand new Federal rounds. everything shot like the stuff you buy in a store.

3 - i started reading more into this subject of reloading - a moment of zen - uh i need someway to read these puppies or "Calibrate" my loads tighter i think - started thinking about humidity, scale consistency, ect. - velocity!

4 - before i reloaded anymore, went to thehighroad.org and posted a question

once again - thanks

 

[dakotasin]

not sure what you mean by velocity being a constant...
if you mean what i think you mean, you know what i mean???

anyway, if you mean it like that, velocity is not a good constant. you may get some pretty wild swings depending on the type of powder and weather conditions (wanna go from safe to need-gunsmith-now??? sit some cases out in the sun that use a ball powder, then run 3 or 4 thru your rifle on a 95-100 degree day).

a good load using good powder/primer combinations will be pretty close day-to-day, but it will still vary some. some days it will vary more than others.

as far as shot-to-shot, no matter how careful you are w/ your loading, you are still going to get velocity standard deviations. you want the sd as low as possible (teens or lower) - all that means that this shot may or may not go exactly as fast as the next one.

 

[Ol` Joe]

Feel free to disagree, but if you think that Sierra's published Max loads are running at SAAMI maximum pressures in there rifles, you are delusional. Do you think that for one moment their lawyers would allow a TRUE SAAMI maximum pressure load to be published in the off chance that someone uses it with perhaps a change in brass from a commercial case to a military case with reduced capacity, and has a catastrophic situation?

USSR,
I personally don`t know what the loads in Sierras manual produced in their tests. I don`t even know for sure if Sierra pressure tests or works up their loads by case head expansion, or a computer model, as I`ve heard some companies do. I do know Speer now claims to pressure test thier loads, where as in the past they stated they used case head measurment as a referance to the pressure the loads were giveing. I also still stand by my belief that they list the loads they feel as being at max pressure. Note Speer has lowered quite a few of their older loads.
Remember too the loads, if pressure tested , are worked up in SAAMI std barrels and chambers that are much tighter then a normal factory chamber. Loads will give as a result, lower pressure in a factory gun then in a test barrel. Velocities also are normally lower because of this as most have found when they crono their loads. Sierra bullets COULD be of harder core or thicker jacket material giving more resistance because of increased bearing surface or be influenced by other component differances from the loads in the other manuals you seem to believe are more honest.

There is also the possiblity they noted pressure swings wider then those foundby other companies. The SAAMI spec has not only a MAX AVERAGE but a MAX ALLOWED individual pressure. The loads may well be under avg max but one hit the allowed max during testing. Again I don`t know, I`m just stateing possible reasons for different charge listings.........

I'm not sure that's true, either. I think some companies are more conservative than others. One genuine example: look at Hodgdon's reloading manual and Speer No. 13, for .380acp. The MAX load in Hodgdon's book is LESS than the STARTING load for Speer 13 for some powders

Dave, take another look at the books and compare like bullets and powders. I find only the 90 gr Speer and Tite Group as a matching load in the Speer #13 and Hodgdon #27 manuals. The Speer book shows a starting load of 2.7 gr and max of 3.1gr with this bullet. Hodgdon lists 2.7 - 3.2 gr, vel is Speer 930 fps vs Hodgdon 953 fps both in 3.75" bbls. Pretty close.......

Lets look at other 380 loads. Hodgdon uses Hornady bullets for their other loads (useing HODGDON powders) a 90 gr JHP and a 100 gr FMJ.

The 90 gr in Hodgdons #27 shows 3.2 gr - 3.5 gr of H38. and 2.2gr - 3.2 gr of Tite Group.
Hornadies #5 shows 2.9 - 3.5grs of H38 and 2.7 - 3.2 gr of Tite Group with the same bullet........Hmmmmm

For the 100 gr FMJ Hodgdon shows 2.9 - 3.1 grs of H38 and 2.6 - 3.0 gr of Tite Group.
Hornady #5 lists 2.5 - 3.3 grs of H38 and 2.3 - 3.0 gr of Tite group.

Considering Hodgdon used CCI primers and Hornady WSP the loads are remarkably similar. Remember every component change and test platform differance will change the pressure and there for the max listed load. You can`t compare apples to oranges with load data. The components have to be exact to get similar results, Any change will alter your results. This is a good example of why one should use the data from the bullet manufacture he is useing to work up his loads.

If you use the exact same brand components and work up with a crony to the same velocity you SHOULD be in the ball park of the pressures found by the data compilers. Your pressure may be a bit lower or higher but it "shouldn`t" give you problems. Use Speer data with Nosler bullets doing this and things could change.

 

[USSR]

If you get a chronograph and your velocity is higher than listed it doesn't mean that your exceeding SAAMI maximum pressure. Likewise you may be well below the listed velocity for your load and be at or exceeding SAAMI maximum pressure. Look for pressure signs.

Exactly. Velocity obtained in your rifle has no direct bearing upon the pressure generated in your rifle. Chambers and barrel quality varies, and a similar load in two different rifles may vary by 100fps. Also, I have never obtained a lower velocity than stated in a reloading manual; always higher using the same components. Know what a reasonable velocity for your rifle/load is, run it over a chrony, and check for pressure signs on your brass.

Don

 

[Major Beer]

not sure what you mean by velocity being a constant...
if you mean what i think you mean, you know what i mean???

to clarify that question:

velocity as a constant - i guess i was wondering if velocity should be used a guage to monitor your loads and their pressure since there is no way to measure the cup pressure. is there a relationship between velocity and cup pressure? does hi velocity = hi pressure?

got paid today (yay) i will heading up to my local outfitter for a new chrony and the Speer #13 or Hornady manual. probably do more a lot more reading before i load anymore 9mm.

i can see it is going to be a while before i get into rifle rounds.

 

[USSR]

i guess i was wondering if velocity should be used a guage to monitor your loads and their pressure since there is no way to measure the cup pressure. is there a relationship between velocity and cup pressure? does hi velocity = hi pressure?

Short answer, No. Velocity varies from gun to gun. Two of my rifles, same load; one is 2875fps, the other is 2950fps. Similar cup pressure, but the 2nd one has a Krieger barrel with a better chamber.

Don

 

[pcf]

Major,
Chronograph is good for a common sense check, and determining load efficiency.

While back I had a 7mm Rem Mag that I HAD to get maximum velocity out of. Every one knows that a 160gr bullet moving less than 3000fps is inadequate for whitetail deer. I'm smarter now. As the powder charge increased, so did velocity, however, towards the top end a 2% increase in powder didn't net a 2% increase in velocity, more like .2% increase in velocity, with a significant increase in muzzle blast, report, shortened case life, and shortened barrel life.

When you get your chronograph, you may decide to add that extra 5% of powder but there may be no tangible benefits. You might have more muzzle blast, a louder report, more wear and tear, and that's it.

The chronograph will also help you find a load with the right powder burn rate for your barrel. There is small performance gap between fast and slow powders fired out of short barrels (less than 3"). Testing .357 loads in a 2.5" S&W 65, the difference between max loads of w231 and w296, with 125gr bullets, only netted a 150fps difference. (Definitely not worth it). Out of a 6" 686 there's almost a 350fps difference.

By the way, be a jerk, don't let people you don't know well use your chronograph. Anyone that dumb enough to shoot it, won't be polite enough to buy you a new one.

 

[dakotasin]

While back I had a 7mm Rem Mag that I HAD to get maximum velocity out of. Every one knows that a 160gr bullet moving less than 3000fps is inadequate for whitetail deer. I'm smarter now. As the powder charge increased, so did velocity, however, towards the top end a 2% increase in powder didn't net a 2% increase in velocity, more like .2% increase in velocity, with a significant increase in muzzle blast, report, shortened case life, and shortened barrel life.

yes, this is common - as powder charges go up, the gain in velocity isn't as much as before. most noticeable in short barrels, or barrels that are too short for the chambering (ie, 24" in a 7 mag is on the short side).
---

When you get your chronograph, you may decide to add that extra 5% of powder but there may be no tangible benefits. You might have more muzzle blast, a louder report, more wear and tear, and that's it.

well, recoil goes up, too. not that recoil is a bad thing - personally, it doesn't bother me a bit, but it does increase.
---

The chronograph will also help you find a load with the right powder burn rate for your barrel. There is small performance gap between fast and slow powders fired out of short barrels (less than 3"). Testing .357 loads in a 2.5" S&W 65, the difference between max loads of w231 and w296, with 125gr bullets, only netted a 150fps difference. (Definitely not worth it). Out of a 6" 686 there's almost a 350fps difference.

major - read and understand this paragraph... it is important.

---

By the way, be a jerk, don't let people you don't know well use your chronograph. Anyone that dumb enough to shoot it, won't be polite enough to buy you a new one.

definitely do not lend out your chrony. they aren't that expensive, so anybody that needs one should just go out and get it.

 

[Ol` Joe]

There is a very good artical on velocity vs pressure By John Barnsess (sp?) in the Aug issue of Handloader magazine. He explains the relation of pressure to vel and crono`ing loads to judge pressure.

 

[Major Beer]

chronoy ordered

well - went to my outfitter - after work. they were having a nice sale combined with 0% financing for a year - was preapproved for a bundle and scary for my marriage should i get a Barret 50 bmg too (just kidding)

while my financial info was getting processed, i went to the reloading area to kill sometime and load up on some gear. out of chronographs ok i ordered one

so i did the logical thing - they did not have what i wanted to walk out the door with in that department, so i went to the gun shop where a buddy of mine works - "walked out" with a something else i wanted: 5in Springfield XD 40S&W black on black. been wanting one of these for a while - snap had to have it.

after inspecting my new XD- i ran a box of 50 through it out back -

right reloading: sounds like you can really tweak a load to your rifle. i have not read a whole lot about burn rates yets - i understand the concept. i never considered

The chronograph will also help you find a load with the right powder burn rate for your barrel. There is small performance gap between fast and slow powders fired out of short barrels (less than 3").

lots of fine tuning - looking like an awesome winter sport once deer season out - "reloading season".

 

[45crittergitter]

If you are getting higher than book max velocities with the same set of components, regardless of charge weight, and the book pressure is anywhere near max, I STRONGLY SUGGEST YOU QUIT! The most likely culprit is higher pressure. No such thing as a free ride.

 

[Major Beer]

getting my chrony tomorrow - i think - depending if the store calls me and tells me it is in to pick up.

this should open a few more doors for me - i will stick with pistol ammo for a while until this added level of information comes together. i i am going to hold off on rifle ammo until i get more experience.

i took a break from reloading, made this post is reset my compass since i had some early experience - and some things were coming together and wanted some confirmation - got that -- get a chrony. as stated, did not get that instant gratification i wanted when i went chrony shopping , shucks - had to order it and wait and bought an XD - happy - blah blah - same dilema with a bunch of once shot Federal Brass in 40 S&W gotta reload it

got the die, accumulating the Fed brass, waiting on the chrony - figure start over and rework my thinking on 40. i can see investments in equipment - etc. be safe

great forum once again - having fun playing - therefore i reload = shoot more =reload = shoot more ...