Pressure Signs?

[Bowfishn]

terribley sorry, I see my cartridge information didnt update correctly giving bogus results. I see the load now shows 66,712 pressure not double that as I said before.

I figured it was probably an input problem, I had to check and recheck mine to see if I was doing something wrong, but it kept coming up with the 66K+, then after raising to the 3000+fps the pressure is above 70K

From "Berger Bullets Reloading Manual 1st Edition"
140 Berger Alliant RL-17 37.8 max load 2692 fps

QL shows this load with the 24" Barrel as 2652 fps most likely due to powder lots tested.
When adjusted for their 2692 fps pressure would be 51,514 psi which isn't max pressure for that cartridge, but a safe load that would account for other variables and the fact your published data could lead to law suits.

I had 3 loadings on my Nosler cases with 49 gr RL26 behind 143 ELD-X bullets @ 3040+ in my Creed and the primers are still tight, but I do believe QL is correct in the pressures being high. Besides the load at 3000 fps is more accurate.

 

[Barrelnut]

Assuming this load was worked up in moderate temps, it might really start to show pressure signs in hot weather.

 

[MajorSpittle]

I worked up loads for my 30-06 using quickload and Reloader 17. I put in seating depth, fired case capacity, .... and what I found was that QuickLoad was off by ~ 3gr of powder compared to velocity when fired over 2 chronographs. (pretty **** dangerous when loading up a 208gr bullet)

I no longer trust QuickLoad at all, especially with Reloader 17. If you have to adjust the burn rate of powders to get it to match your velocities, how can you trust the chamber pressures it spits out?

I am new to Reloading but learned quick to use multiple sources, start low, and verify velocity. I worked up a lot of loads with QL to ladder test this spring, but ended up pulling the bullets on half the rounds because QL was so far off.

 

[dsculley]

You have to tweak the powder burn rate in QuickLoad because the data in the program was developed with one batch of powder and your batch may vary. There is no way the program can take into account manufacturing variances. I have found that if I shoot a relatively mild load to test seating depth, I can chronograph these rounds and use this data to tweak QuickLoad. Doing this, I have found QuickLoad to have very accurate predictions.

YMMV,

 

[Mikecr]

+1 Dennis
Just work up (the golden rule), and lock into calibration of QL for your situation.
If you don't know that you're just as dangerous with manuals.

 

[eklarsen]

If you enter in all the corrections for H2O capacity and seating depth etc... info from QL is dead on in most cases, it is a trusted source for me. RL 17 is a little persnickety when it comes to environmental changes but QL results are always within a few FPS so I trust it.

 

[Milton02]

Sorry guys, ain't been able to check this in a while.

The brass was new!

- Ian

 

[MajorSpittle]

You have to tweak the powder burn rate in QuickLoad because the data in the program was developed with one batch of powder and your batch may vary. There is no way the program can take into account manufacturing variances. I have found that if I shoot a relatively mild load to test seating depth, I can chronograph these rounds and use this data to tweak QuickLoad. Doing this, I have found QuickLoad to have very accurate predictions.

YMMV,

QL was 16% off. It was showing that 57grs would give me velocities that I was getting with 54grs. I don't think that any of the major powder companies accept that kind of a lot to lot variance in powder.

 

[RockyMtnMT]

What are the thoughts in the variance from barrel to barrel? Some are faster than others.

Steve

 

[Barrelnut]

Barrel life is another consideration. If you are running a 6.5x47 Lapua at 6.5x284 Lapua speeds. I'm thinking you're gonna get 6.5x284 barrel life.

 

[Bowfishn]

QL was 16% off. It was showing that 57grs would give me velocities that I was getting with 54grs. I don't think that any of the major powder companies accept that kind of a lot to lot variance in powder.

Not really sure what happened with your loads but I checked QL against Alliants reload data for RL17 and the 30-06 loads for powder charge vs published velocities.

200 gr bullet was off by .7% 24" barrel
180 gr bullet was off by 2% 22" barrel
165 gr bullet was off by .5% 22" barrel

QL showed slower speed requiring the percent increase to equal Alliants.

I do not know if the 22" barrels were from same rifle or not.

I had to tweak my loads .4% when I switched lot numbers with rl26
new lot was slower than first lot I tried, I now have 5 lbs of same lot.

QL is a good means of comparing powders and bullets for a cartridge, but as with load manuals start low and work up. By using velocities obtained by shooting and comparing with predicted QL velocities you will know if you are approaching high pressures.
If I test a load and it is 100 fps faster than what is projected by QL or load manuals, is it because I have a magic barrel that causes bullets to gain velocity without pressure increase or is it because something is causing higher pressure and velocity, causing me to approach increases with extreme caution.
Just my 2 cents.
gun)

 

[Milton02]

You're absolutely right on the barrel life, luckily, the load didn't shoot accurately at all. I've settled on one that shoots around 2840 at just over a 1/4 minute. More testing to follow, but those were the first rounds of results.

What are typical velocities you guys are getting for the 6.5 Lapua? I know with all the variables, its apples and oranges, but it'd be interesting to hear.

-Ian

 

[Mikecr]

The brass was new!

Then this was a forgiving situation w/resp to pressure, and problems. You should start over, working up again with fire formed brass.

 

[RockyMtnMT]

I can say that my current Lilja barrel is 100fps slower than the last from McGowen. Same length and same reamer. Different action. With most barrel makers having a .0005"+- in tolerance pressure required to get to vel has to vary too.

We received barrels from another barrel maker that were over spec to the point that our smith was not willing to chamber them. I think many smiths would go ahead and you would never know. Given the tolerances in off the shelf rifles I am sure there are some large dia bores available.

Point being some barrels are going to show more pressure than QL and some less. Start low and work up.

Steve