I Know that this is an overdone subject, but here it is again. Every time that I want to try a new powder or projectile, I go to my load manuals for guidance. This is where the head scratching always comes in. I just got a new batch of .224 53gn SMK's and went back to my range books to check my past loads. I found in the past my best load at the range for 53gn smk w/ H335 was 25.0gn. After reviewing old data, I looked in Hornady 9th ED. and Sierra V/8 to recheck for safety. Low and behold, up jumped the devil once again. Sierra shows max load as27.6, Hornady as 25.4, and Hodgdon as 26.0. I try to play by the rules, But once again , what are the rules. This is a 2.2 grain difference. How do you sneak up to a safe load economically with differences like this? To take it further, Sierra lists their accuracy load as 26.9gn. I loaded some 26.9 and took it to the range with some 25.0gn loads I shot the first round in my heaviest bolt gun and compared the primers and necks. They were the same and showed no overpressure. I then shot a 5 shot group of both loads at 100yds at a precision target and the 26.9gn load was little better than 1/8" better than the 25.0gn load that I had worked up in the past. O.K., enough for the prelude. I looked for info in the manuals that might account for the differences in load data. Didn't find it. Someone might be able to point me towards it in the manuals. Looking at a Bond receiver tends to make me think that the only difference in chamber pressure should be jump. I understand lawyering up, but why do we not have industry standards for this? I have read enough of these forums to know that there will be those who will start off by saying that you will understand after years of experience like I have. That doesn't solve the problem. You only get years of experience with years of experience. I started reloading in 1962 and I still don't understand a lot of this. What should a young reloader think? Just my $.02 worth.

quote:

Originally posted by AIRBORNE GRUNT:

I go to my load manuals for guidance.

That's it. Don't expect more.

Differences in loading manuals may be attributed to different test rifles, chambers, bore dimensions, powder lot used, primers used, case manufacture, test environmental conditions, test and measuring equipment used, and the author's individual criteria for what makes a "maximum" load.

As the books say, you have to work up loads for your particular rifle. They all have a margin of safety built in for the rifle and components they used. Still, I don't recommend exceeding any manual's max loads. Some people do it regularly but every now and then you hear of a "mysterious" blow-up.

Have fun. Good luck.

The "maximum" load in one rifle may be 5,000 psi below max in another rifle, and 3,000 psi over max in another. The only way you know is to chronograph your loads.

If you look at max speeds for the same powder/bullet weight in each book, you'll see more consistency there than in the actual powder charge weights. That is really what you use as your guide - velocity.

Without a chronograph, you really have no idea where you're at pressure-wise, even following a load book's recommendations.

What are the Rules, you ask? There are so many variables
associated with hand loading that, there can only be general guidelines; no hard and fast rules. Well, not when it comes to max loads that is.
Even with a chronograph you still have no idea about pressures. You need pressure measuring equipment for that.

Don't forget the lawyer effect.

Times change. My old Hornady Vol II simply said the max was a full case or .0005 head expansion.

Thanks for the feedback fellas. About what I expected. As I said in my opening thought, this is an old worn out subject and as such should have been remedied long ago. Grenadier, you mentioned all sorts of variables. Chamber and cases are speced by saami. I also mentioned that I could find no info on the barrels and other equipment used for their data in their manuals. I asked for help finding it to help make sense of their data. Nodak: Chronos are nice within the same parameters, but as I said, without info on the test barrels, it is of little use for comparison. I know that this sounds like a lot of pissing and moaning and beating a dead horse, but it gets back to my original premise that we as a community of re-loaders and shooters have settled for too little from the gurus and suppliers. I read that there are "mysterious" blow-ups when people exceed max loads. What if I only had one manual and it was Sierra, It appears that I could frequently go over the max loads published by others. Would I be a "mysterious" blow-up? Now back to my question, Why haven't we demanded and received better standards and not just reverted to the same old tired rhetoric of it's just too complicated or you just don't understand like me? This is not just me crying because I don't understand, but wondering how we can correct this problem and not just pass it of. Did anyone ever wonder about that proof mark on their new gun. There are specs for these things, but your new rifle did not include the type, size, and manufacturer of the test bullets or the powder charge and if it would help, the muzzle velocity. Maybe tis is only $.01 worth. It gets lonely out here snowed in in the cold woods. Happy New Year!!

Chamber and cases are spec'd by SAAMI! Well, there is no law that makes manufacturers follow them, and even assuming they do, there are relatively huge tolerances allowed. And what barrels do they use for testing? All kinds. And even if they all used the same barrels, the data still would not be uniform. It is not a scientific area as there are too many variables which will never be unified. The max load is only for YOUR rifle, and for that particular set of variables; nothing more.
Proof Marks? Not on US made guns; there are no proof laws here, and many/most makers do not actually proof test firearms. With modern steels, there is no point in it. Proofing would tell you nothing about reloading ammo anyway.
You are not alone; you are surrounded by thousands of other reloader in the same boat.

Does bullet construction have some affect on the max load varying from one bullet manufacture to another?

quote:

Does bullet construction have some affect on the max load varying from one bullet manufacture to another

Yes as to the point say all manufacturers 60gr 223 won't have the same max charge for a given powder. Construction, shape etc will impact it as well as everything else mentioned above.

quote:

Originally posted by ramrod340:
Don't forget the lawyer effect.

Times change. My old Hornady Vol II simply said the max was a full case or .0005 head expansion.

Yup! Back in the day (if memory serves), Jack O'Connor (no relation) liked 62 grains of H4831 for 130 bullets in his .270.

Me? I stick to 59 grains and am happy with 2900fps.

But once I did very carefully work up to 62 grains and found no signs of excessive pressure.

But I've never felt the need for anything faster than 2950fps and I've reloaded some of my .270 cases over a dozen times. I like that.

I forgot one other variable that HUGELY affects chamber pressure; chamber throats. They vary widely among makers, and a long throat will take hot loads that will cause blown primers in another rifle.

quote:

62 grains of H4831 for 130 bullets in his .270.

With a LONG drop tube or vibrator.

quote:

Originally posted by ramrod340:

quote:

62 grains of H4831 for 130 bullets in his .270.

With a LONG drop tube or vibrator.

Some compression might have been involved . . .

quote:

cases are speced by saami.

Really? Well, there are dimensional specifications, which manufacturers tend to skew toward the small side in order to assure their cases will chamber effortlessly in chambers with miniumum dimensions.

But there are no consistent specifications for thickness or hardness. It is the brass case, not the steel of the action or chamber, which is the weak link in the pressure containment system. "Maximum" pressure is more dependent on how thick and hard the case is than on the absolute pressure inside that case. A case which is thin and soft in the head area can dangerously blow out at pressures which are fully sustainable for many shots in a harder, thicker case.

The concept of "maximum" loads is not a terribly useful one.

quote:

Really? Well, there are dimensional specifications, which manufacturers tend to skew toward the small side in order to assure their cases will chamber effortlessly in chambers with miniumum dimensions.

Everyone tends to forget all those SAAMI dimensions have those +/- after them.

I guess since there is a max pressure per SAAMI then the brass would be thick enough to handle that. But how much more would depend on a various manufacturers brass specs