Need help/advise. Strange velocity from reloads.

[JimG]

Go easy on me here because I'm new to reloading!
 
I loaded my first shotshells last weekend. I got the loading data from a 2006 Hodgdon manual. Here's what the manual says-
 
1oz shot, CCI209, Win AA hulls 2.75", Rem TGT12 wad, 19.8grs Clays powder, 1290fps @ 9500 LUP
 
I used the exact components listed except for the wads. I used Downrange DRRT12. The bag of wads says that the DRRT12 is a direct replacement for the Rem TGT12 and CB8100-12. I also used slightly less powder, on average 19.4 grains. That's because that is what the bushing would throw. I also spot checked loads and consistantly got 19.4grs. The shot bushing dropped an average weight of .9882 oz. I chronoghraphed and patterned the loads yesterday and was shocked to see the velocity. The pattern was ok to great (depending on the choke tube used). The avg velocity was 1311fps. I did get one shot that went 1333fps. The gun is a Rem 870 with a 28" barrel. I was expecting a bit less velocity because I assume they used a 30" barrel for testing. I chronographed some Fed Game Shok 1 oz 1290fps factory loads and the velocity was what I was expecting, about 1270fps. I showed the reloaded hulls to a couple veteran reloaders and they thought they looked fine (no signs of high pressure). What gives? I'm using the right components, a hair less powder, a hair less shot and getting a lot more speed than I should. Did I do something wrong or is this a good thing??

[JBlk]

My guess would be that the direct replacement wads are just different enough to cause the change in velocity.The can of powder you have could also be a variance.The main thing is that you don't show excessive pressure.

[curteric]

In all the years I've been loading shot-shells, I've never chronograph-ed my loads. You are using about the same components as I am (Win 209 vs CCI 209). It's the load I use for Sporting Clays. I don't know how to tell pressure signs with shot shell hulls. I do know that the hotter you run them, the fewer reloads you get. I also know that if I start the summer league (12 weeks) with 100 once fired Win AA hulls, I won't have to add more. They won't all survive, but there will be more than enough that I can shoot a round of 50 targets. We can shoot twice at the singles, so I need at least 70 rounds.

[JimG]

So the two of you are not concerned about the odd velocity? Like I said I'm new to this and don't want to hurt myself or others. The guys at the club said don't worry about it and shoot 'em. Just thought I'd get some other opinions.

[DickelDawg]

I've reloaded shotshells for many years and in my experience unless you're showing signs of excess pressure the difference  you're experiencing in velocity is not problem. The difference between your measured velocity and the published velocity could be caused by a myriad of very small differences between your reloads and the tested rounds for which the information was published. At any rate, a difference of roughly 100 fps is minimal.

[JimG]

Ok, thanks guys.

[SHOOTALL]

there are two different AA shells ? could you have the older one with a different base wad ?

[curteric]

There are 2 types of Win AA's. One piece and two piece, both are all plastic. The base wad is separate in two piece. You can look in them and see the difference.
I've never been concerned about velocity. I did some calculations some time in the past and determined that velocity is only important as far as penetration is concerned. At shotgun ranges it is minimal as far as lead is concerned.

[JimG]

These are the older grey AA's not the newer so called HS AA's. And the Lyman Shotshell Reloading manual I have says the load data is interchangable between the older AA's and newer HS AA's.

[SHOOTALL]

true but it could be the cause as could the wad or wad pressure etc.

[curteric]

As near as I can tell, or find out, the only difference between the red and grays, (there are two shades of grey) is color. I use the different colors to differentiate shot sizes. red is 7 1/2's, grey's are 8's.

[SHOOTALL]

the wad is different in older ones and they can be red or gray. I think the older ones were seperate and the new ones are molded in but I could be wrong. I think that makes the walls of the shell either stright or tapered which will effect the fit of the shot wad and pressure.

[.45 COLT]

With a shotshell load, an optical chronograph will read about 30 FPS higher than an inductive chrono measuring the same load. That is fact, I've chrono'd both ways. I don't have an explanation that I'm absolutely sure of as to why that is so. I've heard that it's because the optical trips on the first pellet through, which is travelling faster than the bulk of the load. True or not, I can't say, but it sounds plausable. So, no, I wouldn't worry a bit about your higher velocities.
 
That difference in reading applies only to shot loads.
 
DC