My panties are in a bit of a bunch @ the moment so here goes....
From the following it should be evident that the pressures to which I load are well below anything that could be considered even border line dangerous.
Without calibrated pressure measurement, (read...I'm boxing up the RSI lab to go to a new home) the only criteria/indications of excessive pressures available to me that I understand are:
- Flattened/cratered primer pockets. By cratered I mean primers flowing into the tapered primer pocket entrance filling it and shifting the 'seam' to the outer edge of the bevel.
- Extraction friction. As indicated by increased pressure needed to raise the bolt handle and/or use palm or other object to remove the spent cartridge. (This is entirely unacceptable in a hunting round. Loading, shooting and loading the next cartridge should be smooth and entirely effortless. To be otherwise in a hunting load leads to several levels of misfortune.)
After 43 years with the same military surplus 1908 Brazilian Mauser Action, bolt face and firing pin I know what this old girl is telling me.
My chronographing began in 1968 with an Oehler that used the ink trail screens. It told me the same thing that the current Chrony tells me with with any 130 and 140 class bullet in the 270 Win.
The original barrel was a Douglas Premium 12 twist. The current barrel is a Lilja #4 contour 10 twist. Chambers in each are unique and have different affects on bullets and powder charges. The Lilja is a 'slower' barrel but the extra 3" (27 compared to 24) seems to make up the difference.
The below image shows no excessive primer pressure indication, in fact there's less pressure than when I was using IMR 4350 at the same velocities. These cases are on their upteenth loading with no need of FL sizing yet. (I size 1/2 the neck only. More powder capacity). I also use Winchester brass as it has been ( I haven't had to buy any 270 Win cases in decades) tougher and exhibited greater volume than Remington. If I put the Win. case load in a Rem case it is definitely too hot!
There's another fella here using 7828ssc and getting bodacious velocities out of a winny. I tried his loads and couldn't get there from here.
Here load data from earlier manuals:
270 Winchester Load Data from Manuals.Speer Number 7 -
Copyright 1966. My first load manual. ($2.95)
130 grain Speer - 4831 60gr - 3180 FPS
4350 56gr - 3164 FPS
I shot the 60gr 4831 for several years harvesting several deer. I then got the first model Oehler and learned it was making only 2900 FPS MV.
- Copyright 1970 ($3.00)
130 grain bullet - 4831 60gr - 3213 FPS - 48,500 PSI (Must be CUP?)
150 grain bullet - 4831 58gr - 3015 FPS - 52,600 PSI
170 grain bullet - 4831 57gr - 2819 FPS - 51,200 PSI
Speer Number 9 -
Fourth printing April 1978 (Copyright Pages gone from mine)
This was only 4 years after 4831 became a canister powder in 1973!
Note how loads became more conservative.
130 grain bullet - IMR-4350 56gr - 3058 FPS
IMR-4831 57gr - 3027 FPS
H-4831 60gr - 3021 FPS (Note the diff between H & IMR)
By now I knew the rifle pretty well and N205 briefly became available. I started loading it a a starting point increasing charges and chronographing until I reached the usual pressure signs of the previous load. That turned out to be over 3200 fps by at least 50 fps. I toned her back to 3200 (3196 average over many shots). When N205 was no longer on the shelves I switched to IMR-4350 an loaded to the same velocity. In this rifle that was a charge of 58.5 gr, well over maximum listed, and with "livable" pressures. Though FL resizing had to be done every 10 +/- shots as compared to hardly ever with the N205 load.
Somewhere along the line, not too many years ago I learned that RL-22 was the same as Norma N-205 or MRP. Note that N205, back in the day, exhibited variations in burning rate from lot to lot, the same as Reloader 22 does now. I have been told that while being the same as N205, RL-22 isn't as quality controlled.
Using the same load development as earlier mentioned, though using non-magnum primers, I stopped again at 3200 FPS MV. Pressures were back to where they were with the old N205 loads. This was the same time that I discovered LRH.com and learned that the Douglas barrel was done in. I switched to a Lilja 10 twist @ 27". It shot as good as the Douglas. When I switched to CCI-200s from 250s group size dropped to the teens.
Alliant Powder Reloaders' Guide
2002 addition ($2.50)
Speer 130 Spitz 60gr Reloder 22 - 3160 FPS 61500 PSI
Sierra 140 BT 60gr Reloder 22 - 2930 FPS 58400 PSI
Nosler 150 Spitz 59.5 Reloder 22 - 2910 FPS 60300 PSI
Sierra 150 SBT 58.5 Reloder 22 - 3010 FPS 61800 PSI
Mine just happens to shoot the Nosler and Hornady 140 class bullets at 3200 with 58.5 gr RL-22 depending on the lot and the time of year.
Thus I'm a a grain and a half less than the listed max.......neener, neener, neener
Here goes, I'm sending it......<Submit Reply> <Click> - Bang Flop