[Halwg]

This is what I received from Hornady. I will be shooting Lot 3110213 this Saturday. Looks like my chronograph may be slow, but I shall see.

Hal, I looked up both of these lots in our lab reports and assure you that you are fine.
3091331 had an average chg of 49grs and 2510fps with an average pressure of 45,000psi.
3110213 had an average chg of 51grs and 2530fps with an average pressure of 43,600psi.
I'm not sure where the 200fps spread came from in your testing but this is what I found in our lab reports and
Is not uncommon to see a grain or 2 with different lots of powders and other components.
Thank you

 

[HowdyC]

Thanks, interesting.

 

[CalvinMD]

at least their juggling is in the spirit of turning out consistancy in speed and accuracy

 

[Halwg]

at least their juggling is in the spirit of turning out consistancy in speed and accuracy

But again, I can't get close to their claimed velocities with my gun and Chrony.

 

[Quietman2]

But again, I can't get close to their claimed velocities with my gun and Chrony.

Well, for starters their tests are with a 24 inch barrel.

And additional differences could also be location and weather. Couldn't find that post I wrote a while back on this.

 

[dpe.ahoy]

Some barrels are just "slow" barrels. I've had 3 rifles made by the same maker, shooting the same ammo on the same day vary by more than 100 fps. They were all 22" barrels, chambered in 357 mag. DP

 

[big medicine]

I think that sometimes we get lost in minute details. If none of us had chronos we wouldn't know the difference. Would it make any difference then? In reality when all this counts at that second when we pull the trigger on game does 100-200 fps really make a difference? I don't believe it does.

 

[oscarflytyer]

Bet they are using/testing with universal receiver barrels. A lot of the reload data is worked up with these, as listed in the manuals. I don't know, but certainly suspect that these universal bbls are treated like lab instruments and not like yours and my guns/bbls are. Plus, as stated above, also suspect they are at least 24" long. And shooting indoors/controlled environment - not out on the range with all the crazy atmospheric variables.

 

[Gee Wizz01]

I think that sometimes we get lost in minute details. If none of us had chronos we wouldn't know the difference. Would it make any difference then? In reality when all this counts at that second when we pull the trigger on game does 100-200 fps really make a difference? I don't believe it does.

Amen Brother! When I was young I tried to squeeze every last fps I could out of my ammo. Then an elderly friend told me his theory; "work up the most accurate load for your rifle and don't worry about the velocity" and his other gem "a slow moving hit beats a fast moving miss any day".

Gary

 

[Halwg]

I think somewhere you guys wandered off the point. It was about consistency in the ammo. Their explanation to me from Hornady is completely plausible and I plan on shooting the 2 lots and seeing how they compare. I have the feeling that they will not vary by more than a few fps. What concerned me was Al pulling bullets and having 2.2 more grains of powder and his velocity being 250 fps more than I was getting. I truly think our Chronys are off. I'm convinced mine is running slow.

 

[big medicine]

I think somewhere you guys wandered off the point. It was about consistency in the ammo. Their explanation to me from Hornady is completely plausible and I plan on shooting the 2 lots and seeing how they compare. I have the feeling that they will not vary by more than a few fps. What concerned me was Al pulling bullets and having 2.2 more grains of powder and his velocity being 250 fps more than I was getting. I truly think our Chronys are off. I'm convinced mine is running slow.

No doubt we wondered Hal

 

[2shotal]

I guess I started this whole back and forth when I first posted the difference I found in COAL with the factory ammo which, IIRMC was around 2.578 - 2.594. I also posted at the time that the powder was compressed so much that it was like solid. I then went to the range & and posted results with FPS, energy ft/lb, etc. and that is when Hal noticed the difference in FPS. Further research showed that I had 52.2 grains in my ammo and that Hal had something like 49.9 and that he was about 200 FPS slower. We felt that 2+ grains difference in weight between lots was significant.

Hornady tells us that 2+ grains is no big deal. OK, lets say we accept that. But where I'm confused now is when Hornady says that with more grain weight (i.e. 51 grains) they get less pressure 43,660 PSI than with 49 grains where they are getting 45,000 PSI.

I can understand that you may only get a minimal increase (law of diminishing return) in FPS, but I don't understand how with a 2 grain increase, high powder compression, they get less PSI. If someone in the forum can explain this PSI drop, please do so.

 

[Gee Wizz01]

I can understand that you may only get a minimal increase (law of diminishing return) in FPS, but I don't understand how with a 2 grain increase, high powder compression, they get less PSI. If someone in the forum can explain this PSI drop, please do so.

My thought is that the batch of powder is slower or "cooler" than the other lot of powder, so it takes more powder to get similar velocities. A slower powder may have a lower overall pressure, but the pressure spike could be of longer duration. Remember the factory does not use our "canister grade" powders and their can be significant differences in burn rates between lots. I also suspect there are some differences in the chronographs. I have questioned mine from time to time, and I check it with my 22 rifles and some match grade 22 ammo, as it is very consistent and I have checked it with several different chronographs.

Gary

 

[Dr. A]

Most of this is explained in detail in old handloader magazines. (Ken Waters) I've read on numerous accounts as to how factory loads are driven by velocity and pressure. They use a current lot of powder and decide how much powder is placed in the case to give their "factory load", which will be different minutely from another lot. This is nothing new, and nothing Hornady invented. Its the way its done. With our chrony's and pushing these guns to the utmost, we are suddenly more aware. The internet has partially educated us. unforunately it seldom does the complete job and that is where this thread is coming from.

The devil is in the details, and we have become more aware there are many details. One of thesse is that powder lot variations occur. Nothing is science is absolute. They've long told us to work up new loads with new powder lots. This is further proof they are right. It's hard for me to believe how much difference the chrony will read in May as opposed to Janurary!

 

[2shotal]

Agree with both Gee Wizz and Dr. A. I probably should have expanded on my earlier comment by saying that 'given all other variables stay put (i.e. case lenght, bullet length and weight, primer, and powder)' I could not understand how when you increase amount of grains you get less PSI.

I knew and understood that they make changes from lot to lot, but what I did not realize is how much they can and do change the "powder blend" to make it 'cooler/hotter' so that a significant increase in powder weight (i.e. 2+ grains) can result in a lower PSI. Live and learn. ;D