So how many of you believe the velocities printed in loading manuals accurately represent the velocities produced in your rifles?Before I owned a chronograph,I like many others expected that my rifles were producing the book velocities.However after owning a chronograph for many years,I soon learned that although some loads in some manuals do match what my rifles produce,the majority do not.Variations in chamber and barrel dimensions,lot#s of powder,primers and bullets result in variations in velocities produced between guns of up to 200fps even with the same barrel length.As such,the only velocities that I now believe,are those that I read off of the screen on my chronograph.

I have come to the realization that the accuracy of my loads out-weighs top end velocities.

I do match the published velocities in some of my firearms, some I exceed, and many I am below.

I now just look for the most accurate load and maybe boost it up a little from there for hunting as long as the accuracy is still acceptable for what I am hunting.

But, Yea, chronographs will do that to you.

Good Shooting

HL

In some calibers & rifles the results have been eriely close to published data. Working currently with a .300 Weatherby which was 30 ft/sec's behind the book for several different loads. As we all know there are so many variables which affect the results we get that it is difficult if not impossible to know just where to lay the blame. Have faith, they know we have the tools also!

It would be far fairer to sling mud upon the ammunition manufacturers and their qouted velocities than it is to poke away at the bullet reloading crowd... IMHO

quote:

It would be far fairer to sling mud upon the ammunition manufacturers and their qouted velocities than it is to poke away at the bullet reloading crowd... IMHO

I use the stated velocities to select powders to try in different loads. The numbers themselves are only approximate but usually the velocity relationship to individual powders is close.

Stub:

just like the load data itself, I look at the velocities obtained as a general recommendation...results will vary per rifle in either direction, up or down....

I have had some loads be off by 200 fps or better, both high and low...

Seating depth alone can vary that.. I like long throats if the magazine will handle them..which frequently gives me higher velocities...

cheers
seafire

The variance between book and real velocities, lies in your rifle. With my tight chambered, 25" Shilen barreled -06, I get velocities that are within 5 fps (yes, five fps) of the Nosler manual. With the same barrel at 26" and a slophole chamber I couldn't get within 250fps of book.
Same barrel, same lot of ammo, different chamber tolerances, 1 gunplumber vs a real gunsmith.

Tricky question. Well I have factory barreled rifles and custom barreled rifles. The factory rifles generally are within 10% of published values. My Krieger barreled rifles produce much higher velocities and pressures than any other barrel type I have. My Douglas barreled rifles are close to factory barrels.

Some loading manuals, particularly Accurate Arms, the minimum charges will blow primers. I really don’t trust their data and use a chronograph to develop my own loads with Accurate Arms powders.

When developing loads I use the load manuals as a guide for max velocity and max charges. I try to stay within the max and min velocities when doing load development for a new cartridge. I believe that velocity is directly related to pressure. A chronograph is a great help on that. I will try to shoot factory ammunition for a data check as these rounds were developed using pressure barrels.

All in all, I think you have to establish your own confidence levels in your own rifles. I am very familiar with the .223, 308, and 30-06 having shot tens of thousands of rounds in these calibers in competition. I have shot these rounds in hot and cold and have determined in my rifles which loads are safe, consistent, and won’t pop primers in 100 F temperatures. Generally these loads have been developed with two bullet weights, one out to 300 yards, one at 600 yards. My recommended loads in these calibers are mid loading data range in most loading manuals. Which tells me that their maximum loads are way too high for all weather use.

I can say that my 600 yard loads are slower than what I see in published in loading manuals. And if I try to get to their maximum, I blow primers. Maximum loads are tricky and just a change of case or primer or powder lot will cause pressure problems. Even though the velocities are below loading manual maximums.

As for pistols, my velocities are generally 200 fps lower than factory loading manual maximums for magnum cartridges. I don’t know how they can extract cases out of their barrels with the maximum charges they list. For standard cartridges my velocities are close to published data.

quote:

It would be far fairer to sling mud upon the ammunition manufacturers and their qouted velocities than it is to poke away at the bullet reloading crowd... IMHO

Not too far off base there. A while back I ran a chronograph test of some Winchester Silvertip .308s and compared them with Winchester Silvertips in the 30-06. In 22" barrels, the .308s were slightly faster. As I had 30-06 rifles with 24" and 26" barrels as well, I compared the 06 ammo in those as well. The only gun that came close was the Ruger #1B with a 26" barrel and it was still 50 FPS slower than advertised velocity.
As the discussion is on reloading manuals though, why did Sierra shoot their 7x57 loads though a 29" barreled rifle? Their latest manual now shows they're using a 26" barrel. How many of us use a 7x57 with a 26" barrel?
Another manual is starting to use 26" barrels for standard rounds like the 30-06. Seems to me, that they ain't cheatin' fair. To me, data of that type is as useless as mammary glands on a boar hog.
Years ago, I loaded up a batch of .270 Win. with the 150 gr. Nosler Partition. No chronographs available at the time. Then, in 1981 IIRC, a fellow was kind enough to allow me to run my load over his instrument. He asked me what I thought I was getting and based on averaging from several manuals, I said about 2,800 FPS.He wouldn't say what his chronograph was showing until I'd shot a full five round string. He then asked if I wanted to sell that rifle. The velocity was 2,999 FPS average. A few years back, I ran some of that load over my own Chrony and got the same results. The rifle is an FN Mauser with 24" barrel. NO! It's not for sale.
According to the Winchester loading booklet, 69.0 gr. of WMR should give 2,750 FPS with a 200 gr. bullet from a .300 Win. mag. My M70 with 26" barrel delivers 2,930 FPS. Surely, 2" more than the more common 24" barrel shouldn't make all that much difference. beats me, but I'm not complaining.
In the case of both of those rifles, they are extremely accurate, the .270 putting three shots under a dime. Fire two more and you can still cover the group with a nickel. The M70 will do .75" for three shots with that load. It's also not for sale.
Both rifles show absolutely no signs of pressure. case head and expansion ring measurements are less than or equal to factory loads. I'm a happy camper.
Paul B.