How many load data sources do you consult ?

[hounddawg]

When working up a load I always check as many sources as possible and am always amazed at the differences I find on various sites. I am going to be loading some 175 gn Barnes Match Burners with Accurate 2520 powder in the .308 Win. tis morning and testing them this afternoon in a bolt gun

First place I looked of course was the Barnes site - 44.0 gns minimum 48. 9 maximum from a 24 inch barrel

ok - lets look at Western Powder - 39.9 gns minimum - 44.3 maximum for a 175 SMK also from a 24 inch barrel but the MB and SMK prfiles look about the same. hmmm pretty wide discrepancy

How about a Nosler, the SMK, MB, and CC all have pretty similar ogives. 39.5 min - 43.5 max also from a 24 inch barrel

ok lets look at the Sierra manual and as usual it is one of the more conservative loads 36.1 min 41.1 max

Now being a conservative kind of reloader I will be starting with 39.0 and working my way up to 41.7. Depending on how it groups today and if I see any pressure signs I may try a second higher test set next week.

I am wondering if how many of you guys also look at multiple sources also, I do not want to consider what may have happened if I had just went to the Barnes site and left it at that. Does anyone here want to speculate on why Barnes loads are so much higher. Same test barrel length and the Match Burners, the Sierra Match kings, and the Nosler Custom competitions are virtual clones of each other

 

[Bart B.]

Do all those barrels have the same chamber, bore and groove dimensions?

Do all those bullets have the same jacket hardness and diameter?

What about peak pressure, are all the same?

 

[HiBC]

A far as your specific question abut the Barnes data 48.8 max...I'd have to say "I don't know. Call them". I do not take for granted data that seems odd.

I generally have the load manual from my preferred bullet manufacturers .And I have manuals from powder manufacturers. I confess,some of them are dated.

Most of the bullets I use are Sierra or Nosler. I have both books (along with Hornady and an ancient Speer)
Hogdon is online and they cover most of my powder.I have not yet explored Barnes. I do not have Barnes data. I have the older red Accurate book. I prefer to start with data from my component manufacturers. But I cross reference other data .

Barnes copper bullets may well have different data than a cup and core Sierra.
So I would be reluctant to jump to conclusions, but I'd consider the cross reference "context" or a "Yellow flag" . A max load approx 5 gr higher than the rest would need verification. My intuitive guess would lean toward a lower max charge for Barnes. I dunno....maybe if it has the grooves turned in it the resistance would be lower.

Every time I've called a component manufacturer and asked for tech help I have been treated very well. I give them the crediblty,they do the testing.

I would think Barnes would greatly respect that you verified that 5 grains was correct. Staying safe is good business.

I'd do that before I popped a cap. I also monitor the chronograph against the data. Of course,it won't be exact, but it needs to be about where I expect or its another yellow flag.

 

[lugerstew]

I kind of wish all the load data had about 3 different ambient temperature differences and the corresponding pressures they produced, like for instance the pressures and fps of a 10 deg. day,,, a 60 deg. day and a 95 deg. day.

 

[hounddawg]

it's a whole lot simpler and safer just to check multiple sources the start low and work up. I ran into this once with Hodgon load data for 142 SMK's in a .260 Rem and popped a primer almost all the way out on the minimum load. Chronoed faster than a 120 gn bullet. I came home pulled the rest of the bullets, did a cross check like this and found out the starting load from Hodgdon was higher than the max load from other load sources. Call me a over cautious but to me this is just another red flag on never to trust a single load source.

Part of it may be that each of those data sources is for multiple bullet styles from that manufacturer.

@bart 4.5 - 5.0 gns I don't think that much of a difference cannot be explained by grooves and copper hardness.


CAUTION: The following post includes load data generated by calculation in QuickLOAD (QL) or Gordon Reloading Tool (GRT) software is based on particular powder lots, the assumption the primer is as mild as possible, and assumptions about component, chamber and gun geometry that may not correspond well to what you have. Such data should be approached by working up from published starting loads. USE THIS DATA AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL, nor QL's author or distributor nor GRT's author assumes any liability for any damage or injury resulting from use of this information or information derived from it.
Quickload does not have that bullet listed but a 168 SMK is almost at PMax aroung 46.0 gns. Gordons at 42.0. Those were calculated off my case capacity

 

[Bart B.]

I kind of wish all the load data had about 3 different ambient temperature differences and the corresponding pressures they produced, like for instance the pressures and fps of a 10 deg. day,,, a 60 deg. day and a 95 deg. day.

How would you verify the powder temperature was at ambient temperature when fired?

Remember that the longer the cartridge is in a hot barrel, the faster its bullet will shoot.

 

[BobCat45]

As many data sources as I can find with reasonable effort, but I tend to place greater trust in data from the manufacturer of the particular bullet I'm loading.

I have several Speer manuals from a number of years, and Alliant .pdfs from a number of years, and Sierra pamphlets, and powder companies on the internet, but like you I am very conservative and tend to start low - and not go any higher than it takes to get the results I'm after.

The Barnes data may be higher than you expect because of the all copper projectile, but their data for the 62 grain TSX for e.g. TAC - 22.5 to 24.5 grains - vs Sierra AR-15 pamphlet for 63 grain SMP of 23.0 to 25.5 for the same powder, does not support this hypothesis.

Also Barnes lists 22.3 - 24.8 grains of Re 15 for the 69 grain Match Burner, and Sierra lists 23.3 to 25.7 grains Re 15 for the 69 gr MatchKing.

The Barnes data looks to be all from 1:12 twist, the Sierra data 1:7 twist.

 

[Shadow9mm]

I have 4 manuals, 3 paper, 1 digital. I consult all 4. Then I check the powder manufacturers and bullet makers load data.

With that said how the load acts in my rifle is the most important thing to me.

I work up from a conservative start towards book max looking for my rifles individual max, but never exceeding book max. flattened primers are ok imho, however if I see cratered of flowed primers its full stop, and one full grain below that for max in my rifle with that load.

 

[hounddawg]

I decided to take the chrono along so the comparing the various velocity data will be interesting. I am using a 24 inch 1 -10 barrel with just over 100 rounds down the tube. Temperature in the low 70's. I tend to run strings fast so there will be minimum cook time in chamber

 

[ballardw]

As a minimum two if possible: Bullet and Powder maker manuals of the bullet and powder I have or want to use if available. The bullet makers tend to include multiple powders; powder makers tend to include multiple bullets. Hopefully I get an intersection between them. Then pick the more conservative of the two for start.

 

[44 AMP]

Does anyone here want to speculate on why Barnes loads are so much higher. Same test barrel length and the Match Burners, the Sierra Match kings, and the Nosler Custom competitions are virtual clones of each other

You seem to be having trouble understanding why the load data differs...
Pardon me for having to be Captn Obvious, but the answer is, or should be obvious...

They are different because they are testing DIFFERENT THINGS!

How about a Nosler, the SMK, MB, and CC all have pretty similar ogives.

Machts Nichts
(doesn't matter)

I trust all the sources to be faithful accurate reports of the results they got with what they tested. BUT, I am also well aware that what they tested is not exactly what I have, and its not what you have, either.

No matter how closely we try to replicate what they tested, we cannot. We can get close, close enough to use the data as a reasonable guideline, but that's all.

EVERYTHING made has an acceptable range of tolerances. And you will find variations within the acceptable range in every production lot. These tiny differences ALL play a part in the total combination.

Statistically, there is a bell curve at work here. The majority of things fall in the middle of the curve (which is why the data is a useful guideline) but there will be examples at each end of the curve.

Similar looking bullet ogives and the same length test barrels only give the roughest of comparisons. Even though they may look the same, they ARE DIFFERENT, and that difference results in differing data.

At a guess, Barnes data is so much different from everyone else's because their bullets are so much different from everyone else's.

Generally I will look at data from 2 or 3 sources, or more, until I find data that most closely matches what I am going to shoot, and use that as a starting point. And its ONLY a starting point, used to see if my gun/ammo combination falls near the middle of the curve, or more to one end, or the other.

I've seen guns with identical barrel lengths shoot the same ammo at different speeds. I've seen gun A, and gun B do just fine with a certain load, and gun C stick cases in the chamber shooting the same ammo.

Pretty much every variation you can think of is possible, though some are much less likely than others. But less likely doesn't mean never.

 

[nhyrum]

Use the information from the manufacturer of the bullet. Different bullet shapes will have different amounts of bullet in the case, even for bullets of the same weight.

You'll also notice if you measure where the lands are in your rifle, changing the bullet you use will change the number.

Sent from my SM-G996U using Tapatalk

 

[gwpercle]

At the very minimum , at least two published sources ...
... that being a manual that's not too dang old ...
But if at all possible ... 4 published sources .

Let me add that on-line load data from powder companies , to me , counts as a good source .
I try not to buy any powder that I can't get good reliable data for , from multiple sources .
I avoid buying powder that is from some sketchy outfit that I've never heard of and the only data is on a website with no phone number .
I also try to buy powder from companies that have been around for a while .

Many years ago , 1970's S&W teamed up with Fiocchi to come out with a line of powders called Alcan , they made primers and shotgun shell reloading supplies also .
AL-5 , AL-7 and AL-8 were the handgun powders touted to do it all ...fast - medium -slow , it was all you needed.
I dumped Bullseye for AL-5 , Unique for AL-7 and 2400 for AL-8 ... the new wonder powders ...yeah right ...when is the last time you saw data for Alcan powders ?
I still got 2 lbs. of AL-5 that I use during shortages and a few hundred small pistol primers ... That cured me of buying powders that haven't been around for a while .
The Speer #8 manual , 1970 printing , does have loading data for Alcan powders if you need any Alcan data ... it has a very large amount for the AL-5 AL-7 and Al-8 in handgun section ... Just saying ...in case you got some !
Gary

 

[Aguila Blanca]

As many data sources as I can find with reasonable effort, but I tend to place greater trust in data from the manufacturer of the particular bullet I'm loading.

IMHO, this is the correct answer.

There's a tendency both among rookies (who don't know yet) and perhaps among old-timers (who may be so accustomed to work-arounds that they forget) that any load recipe is specific to ALL of the components listed in the particular recipe. It is fact, not speculation, the bullets of the same weight and the same general shape/profile may be (and probably are) subtly different in some dimensions or aspects, and don't shoot the same as others of the same general weight and shape.

Consequently, the only load data I believe can be relied on is data for the specific powder and for the specific bullet by brand, shape, and model. Referring to data for "similar" bullets may be used as an indicator of how much caution should be taken when working up a load, but should not be assigned value equal to the data specific to the bullet you're shooting.

 

[rclark]

For me, two at least, unless it is an o' tried an true. For example, every one knows 8.0g of Unique/Universal under a 250g RNFP or 255g SWC is safe and a good load in .45 Colt. No need to look further. Since I shoot lead bullets, usually the 'main' references for my sixguns aren't a lot of help because they cater to the jacketed crowd mostly. But there are still plenty of references like Lyman, Speer, Lee, magazine articles, reviews that get you in the ball park on new powders for bullets of 'about' the same same shape and weight. Remember you are going to be starting low to medium and work up to where you want to be anyway, so it doesn't matter if the 'shape' or weight is a bit different (NOT radically different like full wadcutter vs. semi-wadcutter) . Research is the key. Even, yes, seeing what others have loaded. Doesn't have to be exact. More references you use, the more confident you can be of a starting load. My 2 cents.

 

[RC20]

I cross check Sierra and Hornady for the most part (only Sierra lists 6.5 Lapua so used additional sources)

Each has a number of bullet types in any given category as well as common powders (all of which I have).

I don't start at MAX loads and if its a safe load in all the styles of bullet from ELD to Blunt Nose, that is good enough for me as a start.

I have pushed a few loads up to max and I do look at other sources for that, not often.

 

[hounddawg]

One thing this has brought to my attention is that the majority of the bullet makers there will be a number of bullet styles listed for any given weight. On some there will be more than one bullet weight listed, for example 175 gn and 180 gn on the same chart. For 175 grain .308 Win the Berger manual covers four bullets, Sierra lists five and Nosler has eight. In comparison the Barnes MB is only for the Barnes MB load data is just for the Match Burner. The 175-grain LRX BT has a separate data chart

Being a conservative kind of guy I went with the most conservative data yesterday and started at 39 grains and stopped at 41.7 of Accurate 2520. The Barnes data starts at 44.0 grains and goes up to 48.9 grains.

The rifle is a Bighorn action, Shilen 1-10 twist 24 inch barrel, Triggertech 2 stage trigger in a KRG bravo chassis with a Ezell tuner which has not been adjusted. Temperature was 74 F, sunny and 5- 10 mph winds. At 41.7 I had a 3 shot avg vel of 2565 with a SD of 12 and a ES of 29. Group was nice and round with a vertical of .6 and .70 horizontal. There were no pressure signs and recoil was mild.

I tested IMR 4166 afterwards and velocities were higher and best group was about the same. I am going to save that powder for my .23 and 80 gn bullets since it works as well as Varget for me with that combo

I plan on doing another test of the Acc 2520 this time running from 42.0 up to 44.0 to see if I can get the group size down a bit before twiddling with the tuner. While 2550 FPS will keep me well above supersonic out to 1000 using the Barnes number for BC, the Acc 2520 is not know for temperature stability and I want to get some more data numbers since I will be shooting this from 95F down into the low to mid 30's. I figure I will need to be adjusting powder a couple of tenths at the extremes.

back to topic, I will continue to check 3 or more load data sources for every development and will always start with the most conservative and work my way up. To me that is only sensible and safe

 

[higgite]

Five.

 

[RickB]

I usually start on the internet, of all places. After I've found two or three sources that agree, I look at my print sources.
I'm usually looking for a specific velocity, not near max, so I'll rely on the load development done by others, if they're in near agreement.

 

[Bart B.]

@bart 4.5 - 5.0 gns I don't think that much of a difference cannot be explained by grooves.......

Have you ever shot the same load in two virtually identical barrels except one has groove diameter at .3077" and the other .3087" chronographed to see which one shot the same ammo faster?