H4895 and QL

[308 5R]

QL and H4895 users,

I am doing some preliminary research on looking to put together a batch of somewhat reduced loads for a new barrel in 7-08. I understand lot to lot variance, individual barrels, and the limitations of QL. However like most I’m sure, I have noticed some powders are spot on when all user fields are accounted for (“actual” case volume and bullet length, Wx, etc.), and some have been way off without manipulating powder characteristics. So my question is does H4895 seem to run pretty true on QL compared to real world observations? Thanks in advance.

Semper Fi
Ryan

 

[FeMan]

H4895 seems to be one of those powders that vary significantly lot-to-lot. In my Quickload experience with it, I have to adjust the Burn rate to match my chrono once I get everything else dialed in. I have a new lot of H4895 to try but I expect I'll be tweaking it again.

 

[308 5R]

Good to know. It’s not terribly critical with what I’m trying to accomplish at this point. Its just nice to know when you have bounced all these resources against each other that your starting load bares some resemblance to expectation.

Ryan

 

[Ned Ludd]

In my hands, the preset QL burn rate for H4895 is not usually that far off, but it always needs to be adjusted a little bit. One thing to remember is that in addition to the specific powder burn rate, pressure and velocity are dependent on a number of factors including case volume, bullet weight and dimensions, bore/groove diameter; even the choice of primer can make a noticeable difference. That is part of the reason why the QL people don't try to provide more than a single burn rate factor (Ba) for a given powder, because every firearm setup is different and even the same exact Lot of powder can have slightly different burn rates in different rifle setups. In other words, it is expected that you may have to adjust the Ba factor to calibrate the program for your specific setup. So the necessity of adjusting powder burn rate in QL in order that predicted and measured velocities match for a given charge weight is not solely due to Lot-to-Lot variance in the powder. In fact, the rifle itself and how it relates to the preset burn rate in the program also have a significant input into how much you might have to change the Ba factor to get your predicted and actual velocities to match.

FWIW - I always find MAX pressure by incrementally raising charge weight in QL first, using the preset burn rate and pertinent cartridge dimensional measurements. Then I decrease charge weight incrementally until I reach a reasonable pressure/velocity region for a given cartridge/bullet/powder combination, then decrease that charge weight by an additional 2% for safety reasons, before loading rounds to obtain velocity measurements for the purpose of calibrating the QL Ba value.

 

[308 5R]

Sound advice, I adhere to the same concept, especially backing out an extra bit from a normal 10% down from what should be max. Better to be safe and head to the range with an extra 2-3 loads at the bottom of the ladder. I’m already ugly as it is. No need for some impromptu reconstructive efforts.

Ryan

 

[243winxb]

Title : Powder Lot Variations: A Case Study with H4831 - Hodgdon Extreme



A paper reports on the variations in average velocity for six different lots of Hodgdon Extreme H4831 tested in .25-06 and .300 Winchester Magnum loads.https://apps.dtic.mil/docs/citations/ADA572333
Compared to the lot with the slowest average velocity, the other five lots of powder had higher average velocities ranging from 11.9ft/s faster up to 111.9 ft/s faster in the .25-06 and from 13.6 ft/s faster to 111.1 ft/s in the .300 Win Mag.

To consider the likely pressure variations, consider that QuickLoad V3.6 predicts a muzzle
velocity of 3174 ft/s and a peak pressure of 54371 psi for 79 grains of H4831 using the 155
grain AMAX in the .300 Win Mag. This is very close to the 3177.5 ft/s velocity that results from
averaging the measurements over all six lots of powder. However, compensating for possible
lot to lot velocity variations requires a range of powder charges spanning from 77.5 to 80.5
grains of powder and a range of pressures from 51063 psi to 57910 psi. It is possible that a
load showing no signs of pressure with one lot of powder might not be safe with another lot of
powder. At their web site, Hodgdon recommends working up new loads when the lot number
of any component is changed, and it is evident that this includes a new lot of Hodgdon

my question is does H4895 seem to run pretty true on QL compared to real world observations?

my guess is no. QL is not real world.

reduced loads for a new barrel in 7-08

Hodgdon has " Youth Loads" data using H4895.

I do not own QL.

 

[rammac]

Hmm, you don't own QuickLoad but you somehow know that QuickLoad can't estimate the results accurately. It seems to me that your opinion isn't of much value.

 

[Rdlningcltchdmpr]

QL and H4895 users,

I am doing some preliminary research on looking to put together a batch of somewhat reduced loads for a new barrel in 7-08. I understand lot to lot variance, individual barrels, and the limitations of QL. However like most I’m sure, I have noticed some powders are spot on when all user fields are accounted for (“actual” case volume and bullet length, Wx, etc.), and some have been way off without manipulating powder characteristics. So my question is does H4895 seem to run pretty true on QL compared to real world observations? Thanks in advance.

Semper Fi
Ryan

5744 is a very good powder for this application.

 

[243winxb]

Hmm, you don't own QuickLoad but you somehow know that QuickLoad can't estimate the results accurately. It seems to me that your opinion isn't of much value

I dont need to own one. I can read.
https://www.accurateshooter.com/gear-reviews/test-quickload-review/

WARNING: QuickLOAD is a computer simulation of centerfire cartridge performance. YOU MUST NEVER just “plug in the numbers” and use QuickLOAD’s output for a load recipe. That is foolish and dangerous. There are many reasons why the data QuickLOAD generates may not be safe in YOUR gun. Before loading live ammunition, you should always check with the powder-makers’ most recent load data. In fact, you should check multiple sources if possible, and consult with individuals who actually load for that cartridge. Sierra Bullets offers free load maps which, in general, are fairly conservative. Even when using manufacturers’ load data, start 10% low and work up. Differences in brass, primer brand, and seating depth can make huge differences in pressure. Always reload conservatively and always double- and triple-check QuickLOAD’s output against reliable load data supplied by the powder-makers.

My post above shows the difference between the slowest & fastest lots (H4831) of the same powder. Look at the difference.

 

[308 5R]

No need for a pi$$ing match. Once again, I believe most if not all by now understand that you can’t punch data into a program like this and take it as gospel. It is a predictive tool not a piece of lab equipment. However if you DO use it and you have looked at anything like the some of the newer RL-xx powders on the program some of them have been way off base. I inquired because of some recent personal experience of a load manual and QL both being way out from the real world. If not for playing it safe and starting 2-3% below a starting load(understanding lot variance, component changes, etc) I may have very well been into the red on the 1st or 2nd rung of a ladder test.

If someone has already traveled down a particular road, I consider it wise to simply ask “what’s down there” before proceeding. Thanks all.

Ryan