Over the summer, I did quite a bit of load development for my 300 WM and 7mm-08, which I took to Africa.

I started running out of time and settled on 69.9 gr of IMR 7828 for the 300 pushing a 180 grain Barnes TSX. For the 7mm-08, I settled on 39.3 gr of RL-15 pushing a 140 grain partition. Accuracy was around 1 MOA so nothing spectacular. The problem being these loads were what I would consider very slow 2715 and 2540 fps for the 300 and 7-08, respectively.

So, if I wanted to try and speed up these bullets, would I need to move to a slower or faster burning powder?

Thanks,

With a 180gr bullet, my Nosler book shows 73 gra for a starting load, 77gr as max the 300 WM. Considering you are below the starting load, I imagine it was a little on the slow side. Looks like maybe you were in the section for a 250 gr bullet and not 180???



As for the 7mm-08, my Accurate book shows 39gr RL15 pushing a 140gr bullet at 2488fps, so, again, it looks like the load that is on the slow side. Accurate shows a 42gr max pushing the 140gr pill out at 2714. The first thing I would do is work close to that 42gr max, stoping when my gun told me to.

The 7mm-08 must be a little quirky to load for. The two books completely disagree on RL19, and there are some other pretty significant differences as well.

I am a believer in matching the powder to the barrel. Long barrels generally like slower powders. As for what I'd try next, In a 26" barrel, I'd try Varget and Big Game. In an 18-20" barrel I'd try H414 or H380.

Let me know if you want to bat around a few more idea's.

go to the reloading page on AR and look at the 7MM-08 loading they done. they loaded 43 of RL-15 with the 150. some of my books show 43 grs as max for the 140s .. I am loading 44.0grs of RL-15 and 43.0 of IMR 4064 with the 140s RL-15 is getting me 2910 fps. in my rem. 700 S.S. 24".. i am not showing signs of presser or flatted primers. but W-760 gave me more fps with 46.0 grs but was not as accurate..

get another chrony, those loads are reasonable

My Barnes book lists a IMR7828SSC load of 68.0-74.0 for speeds of 2773-2972 for the 180 in the 300WM.

The Nosler book lists a RL15 load of 37.5-41.5 for speeds of 2596-2827 for the 140 in the 7mm-08.

These are the reasons I'm scratching my head on this a bit. I would have expected higher speeds with these loads. Yet, the test barrel on in the Barnes book was 26" while mine is 24" and the test barrel in the Nosler book was 24" while mine is 22".

Would a difference in 2" per barrel shorter be enough to decrease the expected speeds by 100-150 fps?

I don't think buying a new chrony would do a thing because I shot some factory Winchester 140 grain PowerPoint bullets and they averaged over 2900 fps, but there was some brass smear from the bolt head. Therefore, I believe the chrony is doing what it is supposed to.

Also, I have loaded some N160 in the 300 and got speeds about 100-115 fps over what Lapua had listed as their speeds with a similar grain weight bullet.

Which brings me back to my orginal question, I think I need to use a faster burning powder to try and increase the speeds in these guns?

Thanks,

quote:

Originally posted by graybird:
Would a difference in 2" per barrel shorter be enough to decrease the expected speeds by 100-150 fps?

Not normally, no. But any amount of other factors - e.g. chamber size, differing powder lots etc - might well be.

Besides, although the velocities you are observing do seem a bit on the conservative side, you are certainly not the only one failing to obtain book velocities with book loads. Some reloaders (mostly on the Internet?) always seem to be reporting velocities matching or exceeding book values. For all the rest of us, such velocities are often associated with short case life and loose primer pockets. So if you feel frustrated about not getting to book velocities, feel free to join the club. I'm normally pleased if I get within 100 fps...

- mike

mho,

Thanks for the comments!

I understand that getting book values is not as simple as it might seem. I just found it odd that I was somewhere in the 100-150 fps slower than what I expected, which is based off of the book.

I guess in the end it really doesn't matter, because the 2 kudu, black wildebeest and 3 other critters I tipped over last month using the 300WM and Barnes TSX didn't complain about being hit with a projectile that was travelling slower than the book said it should. Complete pass thrus on every shot as well!!!

In a 7mm-08 2" could be 100 fps difference.
Slow powders in a .270 win usually translates into 100 fps per 2" of barrel.

In addition, my Nosler #6 uses Rem brass, if you are using a thinner brass such as Winchester, that could be an additional 50-100 fps difference. Primers can change velocities anywhere fm 0 to 100 fps. So there are alot of variable. Stack up enough of the right variables, and your velocity can be much different then expected.

steve's pages for 300 and 180 bullet. It appears you could potentially be 9 grains under max.

I can't think of one instance where my Barnes loads were not higher than what they publish and still completely safe. I have the same outcomes so far with Berger bullets too.

If you were not getting pressure signs, add more powder. That load seems pretty light. I know Barnes run w/ less powder, but sounds like you just need to work up the load a bit. All rifles are dif f& some get book numbers, but most fall a bit short. Congrats on the succesful hunt.

In the .300 Win Mag I use 75gr of RL-22, which is .5gr below book max. This load is a real tack driver with the NBT or AB.

Happy Shooting
sonnyboy

quote:

Originally posted by graybird:
I just found it odd that I was somewhere in the 100-150 fps slower than what I expected, ...
I guess in the end it really doesn't matter, because the 2 kudu, black wildebeest and 3 other critters I tipped over last month ...Complete pass thrus on every shot as well!!!

There you go. Just another situation where a chronograph did nothing positive for you. Only caused a bit of concern that once you reasoned it out, doesn't amount to a hill-of-Beans.

Sounds like a great Hunt - congratulations!

Forgot to mention that I use copious amounts of H1000 with a 180gr-er in the 300WinMag and H414 in my 7-mm-08 with all bullets. Don't know what the Velocities are, nor do I care. Just as you mentioned they Kill extremely well, fly relatively flat and are very accurate.