I know that it is said that the velocity published in books is often somewhat over stated but has anyone found that they are getting more than book velocity from a load?

The background to this is that I'm loading 150 grain bullets in 308W and getting really good velocities, in excess of what I've seen in any book for a 150 grain bullet, with a book max load that is showing no pressure signs for me. It is also very accurate so I'm pretty pleased but was interested in the experiences of others.

It seems more likely to happen, for me, if it's a book useing actual comercial rifles instead of pressure gun barrels. Hod book load for H335 and a 150 grn does amazing speeds in a sav 99, with good case life to indicate tolerable pressures.

It depends on a lot of variables. I recently tested my rebarrelled 7mm08 that gets over book speed with one powder and less than book speed with two others that I tried. Every rifle is a little different and no book can match your rifle but only give you data from a controled test.

I have two different rifles which consistently chronograph higher than published velocities with all loads tested. One is a 243 Winchester on a Dakota 76 Alpine w/22" bbl and the other is a custom 300 Dakota barreled by Shilen w/24" bbl. I'm thinking tight chambers and bores in both cases.

Certainly chamber and bore tolerances will have and effect, but what about barrel length? Do you have the same barrel length and twist rate as what the book is using?

Thanks to everyone for the replies, it is good to see that this isn't a unique event as I keep looking for pressure signs and am a little concerned.

My barrel is about the same length as the book figures that I'm working on, in fact I might have 3/4 inch more than the book. I'm using RL15 in a 308W Blaser R93 and am seeing nearly 3000fps from a 150 grain Hornady Spire Point. I didn't set out to get such high velocity: there is a minimum legal muzzle velocity for shooting deer here in the UK and I had worked up slowly to a load which I then discovered was probably on the ragged edge of being legal. So, I worked up to the next accurate load and last week got the chance to shoot it over the chrony. I was amazed to see that it was moving at 2982fps.

It is always possible that the chrony was wrong and I intend to try and shoot a few more over it at some point but it is always useful to tap into the knowledge available on here and get some additional views on what I'm seeing.

Sure, higher velocities for a given load than recorded in someone's "book" are not infrequent. Sometimes the higher velocity is a result of higher pressure due to differences in chambers and barrels; other times it is due to using a longer barrel than the data source; still other ocassions seem to be due to having one of those elusive "fast" barrels.

I own a couple of guns which have those "fast" barrels. Whether due to some relationship or purely by chance, most of the "fast" barrels I've come across are also accurate barrels. Perhaps this is due to an especially smooth internal finish?

It awlays depends. What book, what rifle, waht exact components? It's not uncommon to beat some book loads w/ certain rifles. Only your rifle & load over the chronograph matters.

quote:

Originally posted by Stonecreek:
Sure, higher velocities for a given load than recorded in someone's "book" are not infrequent. Sometimes the higher velocity is a result of higher pressure due to differences in chambers and barrels; other times it is due to using a longer barrel than the data source; still other ocassions seem to be due to having one of those elusive "fast" barrels.

I own a couple of guns which have those "fast" barrels. Whether due to some relationship or purely by chance, most of the "fast" barrels I've come across are also accurate barrels. Perhaps this is due to an especially smooth internal finish?

I agree. Most of the time the book velocities are higher than the real world performance. But variances, such as those pointed out above, can cause the difference in velocities. A good chronograph can be a valuable tool. I've found that when I use my chronograph with my buddies out shooting and they request to shoot over the chronograph that I warn them not to expect reaching the book velocities. Most of the time the actual velocities will come up short by 50-150 fps. I think, maybe, once or twice the actual were higher than the book.

That said, one of my buddies had two 22-250's one with a 22" barrel and the other with a 26" barrel. Over the chronograph the 22" barrel was about 35 fps faster than the 26"!!!!!!

Here's an example I ran into very recently:

7mm Remington Ultra Magnum
160 grain Nosler Accubond
Retumbo
WLRM

Nosler Reloading Manual #6
92 grains maximum load at 3212 fps

Hodgdon Reloading Data Website
94 grains maximum load at 3212 fps

My chrono
93.5 grains at 3350 fps


?????

quote:

Originally posted by rcamuglia:
Here's an example I ran into very recently:

7mm Remington Ultra Magnum
160 grain Nosler Accubond
Retumbo
WLRM

Nosler Reloading Manual #6
92 grains maximum load at 3212 fps

Hodgdon Reloading Data Website
94 grains maximum load at 3212 fps

My chrono
93.5 grains at 3350 fps


?????

Again, what test platform, bbl length, exact components? Even in seamingly indentical rifles, you can see 100fps swings in vel. Throat dims, wear, exact chamber size, no two rifles will ever be identical, even if the chmabers are cut w/ the same reamer. They will be very close, but slight wear on the reamer, bbl steel variations, it's just not possible to get identical reults except by luck IMO.