How to develop starting load w/out published data?

[the_ursus]

Got a .350 rem that wants to test out some custom Bullshop bullets but can't find any data for heavy 270 grainers. I could use some advise on how to find a starting point. All I know to do is interpolate using published data. Is there a better way?

I'm still learning how to choose powders so I'm not sure if the IMR 4895 I've been using for my jacketed 225's will still be good once my bullet weight goes up 45 grains.

[Larry Gibson]

Lots of data for jacketed 250 gr bullets. I'd take a look at those assuming you're looking for high end hunting loads(?). Lyman lists an IMR4895 starting load of 52 gr at 2293 and a max compressed load of 58 gr at 2538 fps. With your heavier bullets I would start at 45 gr of 4895 and work up until accuracy went south or any pressure signs developed. If loading density is less than 85% I would consider a bit slower powder like Varget or 4064 or perhaps RL19 or AA4350. My goal for the hunting load would be 2 moa maximum group with 5 shots at 100 yards at the highest safe velocity with a 95 - 100% loading density. That's how I would do it, other's opinions may vary and someone may already have some data.

Larry Gibson

[stubert]

http://stevespages.com/page8a.htm

[686]

Do not start loading any thing with out some printed data.

[376Steyr]

The .350 Remington has about the same case volume as the .35 Whelen, which is a .35-06. I suggest going with the closest match in published data, which would be the 338-06 with 250 grain bullets. Start low, work up, and wear your safety glasses. Good luck!

[jsizemore]

Glen Fryxell has some cast load data on the lasc site. Maybe you could get up with him and he might have some advice. Good Luck

[Rocky Raab]

Forgive me if this is a bit long, but ...

Three general rules govern the end result of cartridge performance:

If case capacity and bore size are constant, the potential velocity varies inversely at one half the percentage change of bullet weight.

If case capacity and bullet weight are constant, the potential velocity varies at one fourth the percentage change of the bore area.

If bore size and bullet weight are constant, the potential velocity varies at one fourth the percentage change of the case capacity.

If you look through a load manual with a calculator you see that these rules hold true. A larger cartridge in the same caliber, shooting the same bullet, will achieve a velocity one fourth the difference in case size. (If a case holds 12% more, it will get 3% more velocity.) The other two rules hold as well.

All three rules assume that the peak pressure also remains the same. That's the big key. Any time you read about a cartridge that is "improved" and suddenly gets waaaaay more velocity, there is no magic involved; the reloader is just loading to waaaaay above the original pressure levels. Ackley got most of his "improvement" that way: he just crammed in a lot more powder. He judged maximum loads by when his test guns exploded - and he blew them up by the truckload.

If you want more performance in a given bore size, buy a bigger cartridge. Unless you ignore safe pressure levels, so-called "improved" rounds get maybe 100 fps more, and most get only 50.

Let's do some manual crawling and button pushing.

A 308 holds 53 grains of water; a 30-06 holds 66. That's a 24% gain, so we'd predict a 6% gain in velocity according to the rules above. A 308 with a 150-grain bullet gets right at 2800 fps, so a 30-06 with the same bullet and pressure should get about 2970. Actual data shows almost exactly that. Rule three? Check.

A 308 has a bore (bullet base) area of about .0745 in² and a 7mm bore about .0633 in²- about 16% smaller. Rule two says if we shoot a smaller 7mm bullet of 150 grains weight (7-08 Rem) we should get one fourth or 4% less velocity or about 2688 fps. The manuals say the 7-08 gets just under 2700 fps with that bullet weight. Going the other way, a 308 launches a 180-gr bullet at about 2550. A 358 Win with 35% greater bullet base area ought to get 9% more or 2775. The manuals say it gets 2780. Rule Two? Check.

Using those same numbers, we'd expect the 308 changing from a 150-grain bullet at 2800 to a 180-grainer (which is 20% heavier) to get 10% less velocity. That computes to 2520, within 30 fps of the book numbers. Rule one? Check yet again.

[Rocky Raab]

So then, what about that starting load?

I haven't looked up that particular cartridge, so let me make up some numbers.

Under Rule One, if you find a printed load with a 250-cast bullet that gives 2200 fps, you'd expect that a bullet that is 8% heaver to get about 4% less velocity at the same pressure. That would be 2100 fps.

Take the printed load, cut it by 10% and work up until you hit 2100 fps. You will now be at about the same pressure as the load for the lighter bullet.

[fredj338]

Do not start loading any thing with out some printed data.

Well, that is how is should be, but not practical when you are dealing w/ a wildcat round or bullets outside the printed data. I load for several wildcats. I start by match case vloumn w/ another round & then go w/ a bullet wt sim to what I want to use. Start low & work up. Starting data for a 250gr bullet will likely be safe for a 270gr bullet, it is starting data. You can reduce starting data 5% & use that, I have done that w/ heavy bullets in my 338-06. Let me check when I get home, I may have some old data for the 35whelen that shows heavier 275gr-300gr bullets. It's always safe to use heavier bullet data for lighter bullets. Of course if ytou are uising lead bullets you are kind of on your own for any printed data.

[cajun shooter]

Find a case with or close to the capacity of yours and then reduce the load by 10%. I will say this as far as maximum FPS are concerned. If you are shooting something with a 270 grain bullet at any starting load speed that will suffice. The game will not respond any different if that bullet picks up another 150 FPS. It will still have it's feet taken from under it and it's head will still be on the ground.

[leftiye]

Steyr has the easiest apperoach. See if you can find data for .35 Whelen for the Lyman 358009. It's a 280 grainer. (If'n we're talking boolits)

[Catshooter]

Do not start loading any thing with out some printed data.

I also disagree with this advise. So a friend of mine wants to trade me 100 of my Czech surplus 7.62x54r for his 24 pounds of an unmarked unlabeled powder. Smells great, looks good.

If you follow the advice above, you pass on the trade.

But I didn't pass. Did a little research and discovered that the powder must be 4831. Shoots wonderfully in my Finn rifles when loaded exactly like 4831.

In the world of boolits, there are far too many times when you have a fine looking boolit in hand that has no corresponding "printed" data. Forge on, I say.

I would also say that if you have to ask, you have a lot more study/learning to do before doing this sort of experimenting. Or find a buddy with the experience to know what to do and what not to. Both too light and too heavy can be dangerous.


Cat

[Bob Krack]

Cat, I agree with you 100%+!

With the varied audience here and everywhere AND those who are required (by their own mentality) to follow published information ONLY, I ask of you, what about the discrepancies (and obvious (or not) mistakes) between authors and publishers?

I feel absolutely NO obligation not to follow a person that has shown skill and
knowledge above and beyond what the lawyers and corporate politicos have suggested.

For example, I might say "Any load published for a xxxgr jacketed bullet will be safe for use with the same weight cast lead boolit". Well, that is probably a safe assumption for starting loads, but what about the geometry of the bullet vs boolit? How far does it stick into the boiler room?

I could go on and on but the assumption that information that is not commercially published should be ignored is absolutely silly. -- notice I did NOT call anyone stupid!

Bob

[deerslayer]

Very good info!

This should be a sticky!!

[SciFiJim]

+1 On the sticky idea. Interpolation is only part of the process of working up loads for cast boolits.

Theoretically, you should be able to get ANY powder to work with ANY boolit. However, the further you get from actual tested data, the greater the danger of a blow up. Always proceed with extreme caution when working in unexplored territory. For that matter, work with caution when working with published data as well. Misprints and typos can get you killed if you are not careful.

[Bret4207]

Rocky- great post! Never saw that info before.

[kbstenberg]

I went to the site Stubert suggested. Its a very good location for lots of loading inf. It went immediately to me favorites list. Thanks Stubert.
Kevin

[Rocky Raab]

Thanks, Bret. John Barsness and I have both written about those rules. Both of us remember reading them somewhere else, and neither of us can say exactly where. But if you spend a LOT of time thumbing through manuals with a calculator at hand, you'll see that they hold true very well indeed. Where they seem to fail, it's due to a pressure level change; but that's to be expected.

[leftiye]

Powley computer maybe?

[turbo1889]

Do not start loading any thing with out some printed data.

A man with a pressure trace system is light years ahead of someone who works from published load data. When the right (errrr - wrong) variables play together published load data can get you in deep, deep sh*t. I have personally traced published book start loads that produce dangerous 65,000+ secondary pressure spikes in cartridges that shouldn't safely go above about 50-K pressure levels.

Anyone claiming that book data is the sacred grail is a grade-1A moron. Some pet loads out there are safer then some book loads.

When push comes to shove a commercial grade pressure gun, with full curve recording not just peak recording, is the final authority. A $1,500 private user pressure trace system is not far behind with the old copper/lead crusher system falling in below and anything less then that, book loads included, is a roll of the dice and the best you can do is work the odds in your favor as much as possible.

In conclusion, IMHO and IME an experienced cautious loader building pet loads going off pressure signs is a better bet then someone who blindly follows book loads as if they were the gospel truth. Those guys scare me more then the better half of the guys developing pet loads from scratch do.

Don't get me wrong – if your brand new to loading then follow published load data. My point is don't trust it as the gospel truth. If it feels wrong and your getting problem signs then change loads !!! There are quite a few published loads out there that are dangerous if assembled with only the slightest difference in components from what the original developer of the load used. Something as small as a different batch of powder can put some book loads over the deep end !!!

[Bret4207]

In conclusion, IMHO and IME an experienced cautious loader building pet loads going off pressure signs is a better bet then someone who blindly follows book loads as if they were the gospel truth. Those guys scare me more then the better half of the guys developing pet loads from scratch do.

Don't get me wrong – if your brand new to loading then follow published load data. My point is don't trust it as the gospel truth. If it feels wrong and your getting problem signs then change loads !!! There are quite a few published loads out there that are dangerous if assembled with only the slightest difference in components from what the original developer of the load used. Something as small as a different batch of powder can put some book loads over the deep end !!!

Excellent advice, your observation match mine. The differences between individual guns of the same make even can be enormous.

[the_ursus]

Thanks guys, for all the advise and warnings. I'll be going back through this thread soon to take some notes and do a little more research before proceeding with the loading.

[Wayne Smith]

Don't get me wrong – if your brand new to loading then follow published load data. My point is don't trust it as the gospel truth. If it feels wrong and your getting problem signs then change loads !!! There are quite a few published loads out there that are dangerous if assembled with only the slightest difference in components from what the original developer of the load used. Something as small as a different batch of powder can put some book loads over the deep end !!!

And thus the standard advice to reduce loads when changing any single component! How often is that one overlooked?? It's got to be automatic for the cautious reloader.