Quickload's accuracy and scenars

[Ahbeyra]

I have been toying with some potential 155gr .30 cal scenars in my .308, in quickload that is, and the velocities that it shows that i can get out of my various setups are just plain atrocious, using federal match brass it was stating 2785 fps with a 24" barrel and 44 gr of IMR 4895 at 51k PSI. Maybe I just play it too safe, but I generally dont exceed about 52k and i know for a fact that the scenar is not really worth playing with unless you are pushing it at LEAST 2875 if not 2900+.

This is unsettling mainly because I really want to build a .260 but cant justify it or afford it, and so the scenars with a 2900+ velocity seem like the proverbial "poor mans" .260 if you will. But from my QL predictions, i cant push them even close to that.

So, in short, I am just wondering, WTF are you guys doing to get those things leaving smoke trails like that?!

QL has always been EXTREMELY accurate in predicting my A-Max and SMK loads almost to a 5fps margin every time with IMR4895 and about 15fps margin with RL-15, so thats kinda whats got me worried, anyone have any input on this at all?

 

[Heman]

Re: Quickload's accuracy and scenars

Sir what you are seeing is probably accurate due to your 24" barrel. The old international palma load was 47 + or - .5 of Varget is aprox 3000fps in a 30" if you knock barrel down to a 24" you have velocities you are getting. You will need to increase your charge, but 2900 out of a 24" tube seems rather fast but I'm sure people do it.


I have found Quickload to be very accurate for all my cartridges only issue is N150 powder in .260 load I shoot is 100 to 150 faster than what it predicts. You'll want to make sure you measure the cace capcities of your brass. Take a couple fired cases fill them to the top of the neck with water and add a drop of alcohol to destroy the surface tension. Measure the weight of the case with and without and you will get the volum of water. Also I was told by Robert Johnson at NECO that when you do this place some vasoline in the primer pocket isntead of using a primer as water will go down into a spent primer pocket thus icreasing your volume.

Hope this helps and sorry I didn't have the news you wanted.

 

[Ahbeyra]

Re: Quickload's accuracy and scenars

I have set up quickload with all my measured variables very accurately, but that vasoline trick is neat. I wasnt looking for a particular answer, it just seemed to me that my velocity prediction was really weak, every load and sig that i see on this site shows people pushing those really fast and i was just trying to figure out why i was getting such a low number comparatively. I guess i just assumed that most people were using barrels maybe no longer than 26" for most of their sticks on this forum. time to go see the particulars, back to search! thanks for your input though, learn something new every time i post.

 

[Heman]

Re: Quickload's accuracy and scenars

maybe try 44.5 and 45gr watch for preassure signs and see what you get. To push any 155 at 2900 with a 24" barrel your going to have to run the preasures high, dont be afraid of going above 52,000. My Palma load with the 185gr Berger is right around a max load at 60k for the rifle. 3 firings and the Lapua brass is toast, but it does shoot well

 

[MALLARD]

Re: Quickload's accuracy and scenars

I agree quickloads can accurately predict velocities. But it's max pressure predictions have been way off compared to the results of my pressure trace machine, anywhere from 5-15 thousand off. While 5000 isn't bad , 15,000 is unacceptable.

hahah , the .30 150 scenar with a g7 of .236 @ 2900 fps is hardly a 6.5 140 berger with a g7 of .313 moving at that same speed. That difference is huge. I like the way you put it though

 

[Ahbeyra]

Re: Quickload's accuracy and scenars

I totally understand there is quite the difference in potential BCs, but on paper when you compare .260 scenar vs .308 scenar vs .308 anything else really, each one is a giant step in ballistic goodness. for example, and these numbers are just from bulletflight, but...

.260 139 scenar @2900 fps - 900 yards 22 moa drop and 5.5 moa FV wind

.308 155 scenar @2850 fps - 900 yards 26.2 moa drop and 7.3 moa FV wind

.308 168 bthp match @ 2725 fps - 900 yards 32 moa drop and 9.4 moa wind

the .260 obviously walks all over the bthp, but when you look at the .308 scenar compared to the .260, its... close, as if you saw a chick that a slight squinting made her a 10 instead of an 8

But i would like to hear more about your pressure trace findings, can you explain why you think these predictions are so far off from your results?