Conflicting Load Data?

[kilotanker22]

So I have been loading my own ammunition long enough to know that I need to consult several different manuals and compare them to figure out a good place to start load development.

I have had good success loading for my 270 wsm lately. It really seems to like 140 grain pills. I have been loading 140 grain Nosler Ballistic tips with both H-1000 and Magpro.

I picked up some 140 Grain Sierra Tipped Game King bullets a few days ago and Loaded a few up with H-1000 at the same powder charge of 68 grains H-1000. I have shot this load with the 140 grain Ballistic tip without issue. I figure it would be ok since I had no pressure signs and the Sierra Game changer has less bearing surface than the Nosler BT. Also it is middle of the road according to Hodgdon Data. I generally rely on Hodgdons data, because it seems to be more conservative on expected velocities compared to some others. Also I tend to use Powders primarily made by Hodgdon.

After loading these rounds to test, I decided to check the Sierra Load data since it was the only Data I could find with that bullet. Their Max charge is a full 3 grains less than Hodgdons starting charge with a Swift Bullet. Seeing this suprised me. So I decided to check Nosler Data. Nosler's Maximum charge of powder for the 140 grain bullet and H-1000 is a full grain lower than Hodgdons starting load. They all use winchester cases and WLRM primers, except Sierra who uses a normal WLR primer.

Nosler and Sierra Data have a 140 grain bullet with H-1000 at max velocities similar to Hodgdon's, but using 5-7 grains less powder. Hodgdon is the only Data of the 3 that list pressure.

I feel as though the Sierra and the Nosler Data are very conservative and the Hodgdon Data seems more realistic.

Can anyone with personal experience with this Cartridge, powder and Bullet share some info? Or Maybe run my load through Quickload to get an estimate?

The Sierra bullet is .011 longer than The Nosler But has less bearing surface. It is also not seated as deeply into the case.

Winchester case length. 2.095"
CCI 250 LRM primer
H-1000 68 grains
Sierra 140 grain Tipped Game King
COAL 2.850"
.070" off of the lands
22 inch Barrel

[hounddawg]

I had a bad experience last year with some load data from the Hogdon site, their starter load was pretty hot and at .5 gns above the starter load I blew a primer.

My recommendation is to start with the lowest charge from all sources and work up in increments of .3 or .5 gns shooting 1 or 2 rounds at each step looking for pressure signs until you get either the desired speed, accuracy, or pressure signs.

If you are going to have an error let it be on the cautious side

[kilotanker22]

makes sense.

[RC20]

I agree with that. At worst start 10% below the highest listed grain data.

I have done one cross check of R17, Alliaint said start 10% lower. Horndy had it staring 16-17% lower.

If I have shot a bullet up in the max area, even with a bullet change, I have started at mid loads.

If I see the max was a one source high outlier, I will start under mid.

[std7mag]

Kilo,
Just wait till Monday and call Sierra. They actually answer the phones, and are very knowledgable and helpful.

QL won't list the GameChanger bullets yet. It also only takes bullet length, and boat tail length.
It doesn't actually measure bearing surface.
And why the heck would you start 0.070" off the lands, unless your limited by magazine length?
I've never had a cup and core bullet that took anything more than 0.020" off the lands. Many makes/weights/calibers/rifle makes.

Also, as has been addressed many times over on the forum, a 140gr bullet is not a 140gr bullet.
Meaning if you change from a 140gr BT, it's construction/materials is different from a 140gr GameChanger, a 140gr Berger, a 140gr Speer, a 140gr Swift.. You get the point.
When changing components start low.

[RC20]

Also, as has been addressed many times over on the forum, a 140gr bullet is not a 140gr bullet.
Meaning if you change from a 140gr BT, it's construction/materials is different from a 140gr GameChanger, a 140gr Berger, a 140gr Speer, a 140gr Swift.. You get the point.
When changing components start low.

More discussed. While I do not disagree, loading data from Both Hornady and Sierra (may two main sources) does list a range of bullet types with each table.

I have no problem using their data with a Nossler 175 and starting mid range of their loads.

It may seem nuanced, but the issue would only bite you if you were in the high load areas starting out.

You may not get the same good results with any given powder listed, but several them very likely will.

[44 AMP]

I'm sorry I don't have any personal experience with the cartridge, bullets or powder you are using. But I do have a large amount of experience reloading in general, which may help explain why you are getting what you got, and conflicting load data.

it is because every gun and ammo/component combination can be different.

Most times things fall in the middle of the bell curve, but "stacking tolerances" can result in your gun and ammo combination being at either end of the curve, and there is NO way to know until you shoot them.

Barrels are faster or slower, depending on a number of factors. How YOUR gun handles pressure depends on a number of factors. The same load (and within SAAMI limits) can produce widely different results in different guns.

I had a bad experience last year with some load data from the Hogdon site, their starter load was pretty hot and at .5 gns above the starter load I blew a primer.

This is an example of what I am talking about. I'm sure Hodgon didn't blow a primer in their test gun with the load that blew a primer in Houndawg's gun. Every gun and component combination can be different, how much different can range from undetectable to drastic, even dangerous. And there's no way to know, beforehand.

Also, you need to be aware that all max loads listed are not always max due to high pressure. Sometimes, the "max" listed is just where the testers stopped, for some other reason.

Everyone else's data are guidelines, valuable, useful, but guidelines, the real rules are what your gun shows you works and what doesn't.

[hounddawg]

I'm sure Hodgon didn't blow a primer in their test gun with the load that blew a primer in Houndawg's gun.

probably not but the published load data for that bullet in that cartridge was the high outlier compared to other load data I could find. The load I ended up with was lower by 2 full grains than the Hogdon starting load and I still ended up pulling 2850 FPS for a 140 gn 6.5 bullet. The Hogdon data was up in the 6.5 x 284 velocity range at 3000 FPS +

My guess is the data got screwed up somewhere between the test area and the data input.

[T. O'Heir]

All manuals reflect averages of the data collected using the exact components, including the powder lot, and firearm combined with the ambient environmental conditions on the day of the tests only.
You do not need to compare them to figure out a good place to start. Just pick one. Partial to the Lyman manual myself. It has more loads using more bullet weights(that's what's important. Not who made it) and powders than any bullet or powder makers book. They also give an accuracy load for each bullet weight. Whatever powder is used for that is the best place to start. Usually ends up being the place one stops too.
"...load data from the Hodgdon site..." Yeah. Like how they say use magnum primers for magnum named cartridges but not for non-magnum named cartridges using the same powder. H110 in .357 and .30 Carbine for example.

[kilotanker22]

Yeah.

Sierra's starting load was 52.4 grains of h-1000 I believe. Their max being 63. Hodgdons data starts at 66. Nosler data started at 61.

If I reduce Hodgdons maximum Data by 10 percent my starting load will be right at Sierra's max load.

For this particular data. There is nearly a 20 grain difference from minimum to maximum load across the various manuals. Actually 26 percent difference from Hodgdons max to Sierra's starting load.

[kilotanker22]

Originally Posted by std7mag

Kilo,
Just wait till Monday and call Sierra. They actually answer the phones, and are very knowledgable and helpful.

QL won't list the GameChanger bullets yet. It also only takes bullet length, and boat tail length.
It doesn't actually measure bearing surface.
And why the heck would you start 0.070" off the lands, unless your limited by magazine length?
I've never had a cup and core bullet that took anything more than 0.020" off the lands. Many makes/weights/calibers/rifle makes.

Also, as has been addressed many times over on the forum, a 140gr bullet is not a 140gr bullet.
Meaning if you change from a 140gr BT, it's construction/materials is different from a 140gr GameChanger, a 140gr Berger, a 140gr Speer, a 140gr Swift.. You get the point.
When changing components start low.

I am loaded dto 2.85". That leaves me .015 clearance in the mag.

[44 AMP]

My guess is the data got screwed up somewhere between the test area and the data input.

Always possible, and one reason why I don't trust loads on computer as always correct, one miskey in data input, makes a world of difference, and while it may not be true, I feel that printed manuals get a better "proofread" before being published.

That being said, why would you suspect an error rather than correct data, just because it was different from other sources??

They are using a different gun, and (usually) different lot# components. Different guns simply behave differently, even with the same exact components, and we don't have the same exact components used in the published data. We have, at best, similar components but there are tiny (and sometimes not so tiny) differences. When these add up in certain ways, very different final outcomes result. (Stacking tolerances)


I've seen the same ammo produce over 100fps difference in MV in three guns of the same barrel length. I've seen that ammo require a rod and mallet to remove fired cases from the chamber of one gun, give barely sticky extraction in another and function normally and flawlessly in a third gun.

All because of the combination of all factors in the different guns and the ammo. I'm very confident that published data is an accurate recounting of what the testers got. But while it should be similar, its not guaranteed to be what you or I get in our guns, with our components and loading specifics.

Just because one source gets their max different from others doesn't necessarily mean they did anything wrong, it just means they got different results with what they tested.

[jmr40]

Just because a manual shows a certain load as max doesn't mean you can't use more powder. That is usually simply where THAT source stopped testing. Another source may have tested and proved that it is safe to use more powder. It is quite common to see such differences.

This is why I like a chronograph.

[ms6852]

Originally Posted by hounddawg

I had a bad experience last year with some load data from the Hogdon site, their starter load was pretty hot and at .5 gns above the starter load I blew a primer.

My recommendation is to start with the lowest charge from all sources and work up in increments of .3 or .5 gns shooting 1 or 2 rounds at each step looking for pressure signs until you get either the desired speed, accuracy, or pressure signs.

If you are going to have an error let it be on the cautious side

Totally agree with starting loads of all available data, from different publishers. Response is spot on.

[Road_Clam]

I load for 17 different calibers. I have Lyman's 49th, and Hornady's 9th. Much conflicting data between the two. Lyman's tends to be liability "conservative". Hornady is not afraid to publish "robust" data. Then there's the added online load data which also adds some contradictions such as Hodgton, Alliant , and Sierra. In can get concerning and frustrating trying to digest all the data. Glad I have my Magnetospeed chronograph to keep track of my new loads.

[gw44]

I have for many years used Hornady data and bullets, and will for many more !!!

[RC20]

While I use Horandy and Sierra a lot, I also have Speer, Nossler, Lyman.

They seem to stick to follow me home from a shopping trip.

I also have a number of older books (Horandy 80s as well) and old Sierra and various others my wife had a nice find for me of a Sierra early 70s.

While I don't say everyone should do what I do - Sierra or Horandy and a Lymans is a good combo for reality check.

At times I also use the cross check of the on line stuff.

[kilotanker22]

I think what I will do is lower the hodgdon max data by 12 percent. That will put me at Nosler's start load. That's still a 9 grain section of load data to test.

Honestly I am not sure it's worth it with H-1000. I already have a very accurate load with Magpro. And I probably get better velocity with Magpro anyway.

The Sierra Starting load is 26 percent less than the Hodgdon Max load data. The hodgdon load data online is identical to the data in the 2019 Annual Manual.

The only source of Data for the game changer I got through Sierra. I emailed them and they directed me to Midsouth Shooters supply where the Sierra load data is listed.

They also said that Data from their Matchking and standard game king bullets of the same weight can be used for this bullet.

Now like I said earlier. I have fired the 140 grain Nosler BT at 68.5 grains of H-1000 already with no pressure signs. Although it was only 25 degrees that day. And with the BT having a longer bearing surface, as well as being seated deeper into the case than the Sierra. I feel totally fine with starting in the same vicinity.

Although I find it interesting that Sierra was getting comparable velocity to Hodgdon. While using 6-7 less grains of powder to do it

[kilotanker22]

I also think that it's worth noting that I have had hang fire problems in the past with the 300 wsm, and slower powders. Trying to make reduced loads. Some of them blew primers and some didn't.

That's also why I am weary of using light loads of slow powder in the wsm case.

Nosler's start load is 5 grains less than Hodgdons with this powder. And Sierra's start load is another 9 grains less than that.

[44 AMP]

the problem of pressure excursion using reduced loads of certain slow powder in large cases has been known for some time. Rifles have blown up using reduced charges of some powders for no apparent reason.

I don't know if it has been finally figured out, or not, I do know in past decades it was a very difficult problem to study, because it was not repeatedly reproducible in the lab. In other words, you might fire lots and lots of rounds, all the same and only one, or a very few, seemingly no different from the rest goes KA-BOOM instead of bang.


All I can say with certainty is that if the book(s) say "don't underload this powder", then DON'T!

[kilotanker22]

Interestingly enough. Sierra's start load for the 270 wsm with H1000 is lower than the start charge they list for 270 win. Using same powder and bullet weight.

[kilotanker22]

With those starting loads. The 270 win gets 2700 FPS with 54.4 grains of h1000.

270 wsm start load is 52.2 at 2800 FPS. Seems like that info is odd. The 270 wsm has a higher case capacity. How do you use less powder in a larger case to get more velocity than you did in a smaller case with 2 grains more powder....

I will call Sierra tomorrow and try to verify that data.

[Unclenick]

Sounds like a plan. it is almost certain to be true that different lots of powder were used in developing loads for the two, so the WSM could have had the faster burn rate lot. The short case probably lights a little more powder initially, so it's possible to get those results. Double-check that the guns used had the same barrel length. It would be interesting to run the two with the same lots of powder and primers side-by-side in same-length barrels.

[RC20]

If I can manage to get the Labradar, that is a test I can run in the 7.5 Swiss vs the 30-06.

It seems the 7.5 shorter and fatter does burn a bit more efficiently, will have to do some cross checks there as well.

[old roper]

Sierra uses different start loads. The loads for 270 started 2700fps and when to 3000fps and loads for 270WSM started 2800fps to max of 3250fps.

In Sierra manual for those 140gr bullets in 270 which included 140gr HPBT and 140gr SBT they started @ 2600fps max @ 3000fps Same bullets for 270WSM they started load @2800fps max @ 3100fps.

Why should they put more low end loads for Mag?