Load Evolution

[Art]

A while back I posted regarding loads for .303 British using 215 gr. bullets.

I received a reply with the entire 38th edition (1951) of the Lyman Manual. It showed the maximum load with IMR 4064 powder to be 42 grains. I then got the data from another fellow from the 50th edition, early 1960s I imagine, showing the Maximum load to be 39 gr. of IMR 4064 powder.

This is a concrete example from one company showing the reduction in loads for safety reasons over time.

The same 38th edition shows the maximum load for 174 gr. bullets to be 43 gr. of IMR 4064 powder but my new Hornaday manual shows the max load to be 39.3 gr. IMR 4064.

[emmagee1917]

Yep , two forces at work here .
First , the manuals are written more by lawyers than ballistic experts now .
Second , common sense ain't that common any more.

[Sunray]

The current edition is the 49th. There is no 50, yet.

http://www.303british.com/id14.html

215's are only made by Woodleigh these days. Haven't been used since long before W.W. I either. Well except by Canadian moose hunters.
Anyway, my Lyman 45th Edition(1970) gives 35.0(1698 fps) to 39.0(1996 fps) of IMR4064 with a jacketed 215. No 174 grain data at all. No 4064 on Hodgdon's site either, but that just means they didn't retest with it.
In any case, manuals only reflect the conditions using the particular rifle or universal receiver on the day of the tests. Lyman used a No. 1 Mk III* for the 49th ed. tests. Who knows what Hornady used.
"...manuals are written more by lawyers than..." That's an internet fairy tale.

[joem]

Perhaps the formulating of the p[owder has changed slightly. I try to check load data on two or more manuals to see if there is any difference.

[Art]

The current edition is the 49th. There is no 50, yet.

http://www.303british.com/id14.html

215's are only made by Woodleigh these days. Haven't been used since long before W.W. I either. Well except by Canadian moose hunters.
Anyway, my Lyman 45th Edition(1970) gives 35.0(1698 fps) to 39.0(1996 fps) of IMR4064 with a jacketed 215. No 174 grain data at all. No 4064 on Hodgdon's site either, but that just means they didn't retest with it.
In any case, manuals only reflect the conditions using the particular rifle or universal receiver on the day of the tests. Lyman used a No. 1 Mk III* for the 49th ed. tests. Who knows what Hornady used.
"...manuals are written more by lawyers than..." That's an internet fairy tale.

Yeah I messed up on the edition number of the Lyman book.

I have seen load data with maximums from just over 39 gr to 43 gr. in various manuals for 174-180 gr bullets with IMR 4064 in .303 British. I think that just gives you an acceptable range. My 174 gr. load uses 40 gr. of 4064 powder, doesn't kick much, no signs of overpressure and shoots straight.

You are correct that only Woodleigh makes a 215 gr. bullet. Your 1970 data is what I used and I worked up from 36 gr to 39 gr of 4064 powder (because that was the acceptable powder I had on hand) and the result with 39 gr was the same as with 40 gr in 174 gr bullets, no overpressure signs.

As far as the rifle, Hornady's manual says they used a used a No. 4 Mk 2 for their tests.

I frankly think the old .303 factory loads from the early '60s were probably a little on the hot side. They were listed with a muzzle velocity of 2540 fps with 180 gr. bullets. I remember sticky extraction with those loads in my old No. 1 Mk III*. I have no such issues with that rifle and the new loads since the mid '70s listed at 2460 fps.

[mikld]

Personally, I don't believe in the "Lawyer-ing" of load data, but suspect better testing methods and equipment determine what is seen in manuals. Plus, not every test lab uses the exact same components. The powder lots will vary, the exact bullets (jacket alloy and lead alloy) will differ, and primers will be of a different lot. Each test lab uses different equipment, some use real guns, some use universal receivers and barrels will be of unknown age and wear. Most testing today uses more accurate PSI measurements rather than CUP methods. Reloading manuals list the results one particular technician got using the listed components, with his particular test equipment, on a particular day. Reloading manuals are not hard and fast formula, just test lab results, and recommendations for safe load levels...

[Vern Humphrey]

Yep , two forces at work here .
First , the manuals are written more by lawyers than ballistic experts now .
Second , common sense ain't that common any more.

Actually, the older manuals listed loads based on "pressure signs" more than actual pressure measurements. Now that pressure can easily be measured, loads have been adjusted accordingly.