Actual vs Advertised Myth vs Reality.

[RBHarter]

So heres what I'm thinking at OMG O'clock after a night of really poor sleep.
I have a 30-06' thats launched a few factory loads and a while back I shot some Hornady superformance over the chrony ,nearly 3200 fps w 165s the bullets were all over the berm ouy of a 1-8.5 twist but by the book they'll only go 2900 or so and factory numbers almost always run slightly faster than field numbers. next is a load in the sa,e rifle the books collectivly offer a SPBT 2500fps for 50.0 gr of IMR 4350 but that rifle clocks them in at 2700. So I've concluded that I just have 1 of those ''fast rifles''.

I have a ''mildcat'' based on nothing more than a 6.8 SPCII run in a 7mm bbl and throated for a 7-30 Waters.(due to the 6.8 SPCII having a larger neck dia than the 7mm) using 6.8 data I expected it to be just a little slower weight for weight instead it was faster ,although I relise 5 jacketed rounds isn't conclusive proof of anything It was suprising to see 22.0 gr of RL10x push a 7mm 120gt SP Serria 2230 and a 27-130FP RCBS papered up to .286 and actually wieghing 135 gr 2250.It'll go over 2350 but wierd things start happening to the cases and acroos the Chorny so 2250 is fast enough. This set up runs so effiecently that w a NOE 287-150 (hunter) I had to back it down to just 3.5 grains of Unique to get it sub-sonic at the other w/4350 the same 150s were at 1975 fps. and shooting quarter groups at 100. The 1975 is a product of case limits rather than pressure limits. It should be noted that a 38SPCL is still sub sonic w/158 up almost 5 gr of Unique out of 18'' Carbine ..

Then there's this thing about cast bullets only being shootable to w/o checks up to 15-1800 fps..... sure ok. but I know a 32 Rem (abandoned in 1935,basicaly a rimless 32 Win SPCL AI w/a Weatherby shoulder) that will run a 323-175 R2 Lee over 2100fps modified to a plainbase and sized .323 over 3.0 gr under the Win start loads. Its been a while since I looked at the books but it seems like 2150 was at the max for the Win w/jacketed.

In the intrest of fair disclosure my Chrony work is all done at over 4000' because that's where I live.

So how about it, what do really get vs what advertised ? RD you've got to have 100 examples of PB as well as GC going well beyond the speed limits set by ''common knowledge''.

[Ranch Dog]

So how about it, what do really get vs what advertised ? RD you've got to have 100 examples of PB as well as GC going well beyond the speed limits set by ''common knowledge''.

I don't shoot plain based bullets in my rifles, only in the 25 ACP, 32 ACP, 380 Auto, and 45 ACP.

For the last decade now, I've been using QuickLoad and have fine tuned my settings to where the the suggested performance, with my inventory of powders, produces some pretty good guess that are reflected in the shooting at the chrony. I don't use published data so I can't make the comparison. The reason I stopped using it and switched to QuickLoad was it was tough to figure out what data to use in that I only shoot bullets of my design.

It has surprised me that QuickLoad doesn't take altitude into account at least for the velocity prediction. I suspect altitude has very little impact on the pressure generated.

[RBHarter]

I was moping around this morning and musing through some older posts.

So I thought I'd bump this 1 back up for grins. I'm still musing over several cartridges that are much faster than advertising suggests...

[357cyrus]

In my limited experience with QuickLoad and figuring out how to use it... I've received tips that burn rate of a specific powder from lot to lot can vary up to 10%. When I adjusted burn rates on loads that didn't make sence previously, the numbers finally matched what I saw over my chronograph. So my theory is that factory ammo will have the same fudge factor. Another thing I've come to understand is how much of a difference the temperature of your ammo when you shoot it can have on pressure/velocity. I've got one load that's "mild at 50* and over pressure at 95*

[Steve]

In my limited experience with QuickLoad and figuring out how to use it... I've received tips that burn rate of a specific powder from lot to lot can vary up to 10%. When I adjusted burn rates on loads that didn't make sence previously, the numbers finally matched what I saw over my chronograph. So my theory is that factory ammo will have the same fudge factor. Another thing I've come to understand is how much of a difference the temperature of your ammo when you shoot it can have on pressure/velocity. I've got one load that's "mild at 50* and over pressure at 95*

I have started recording powder volume and weight as a referance of where to load in the future to reach the important recording "Velocity". This is because I have found what you state above to be true. I did read something in the past about manufactures of amunition adjusting loads do to powder batch burn rate.