Load data doesn't match results IRL

[6bra1k]

Hello, and thank you all for allowing me to join! I've been a fan of this page for quite some time and has helped me through some quandries in the past. Ive got an issue ive spent the last roughly 5 years trying to figure out.

Learned reloading from my dad. better part of 40 years worth of helping him and learning. Reloading on my own for approximately the last 6 years. We'd always used the Lyman bible and worked up loads using that. My dad never had a Chronometer and never knew the velocities. Simply went with data from book, and went with whatever load within what the book said, was most accurate.

It wasn't unti lI started doing my own reloading, a bit more financially secure, and wanting to be more high tech, that I got a chronometer and use it whenever I do load workups. But this is when things started to go off the tracks. I have found that real life data isn't matching, or even coming close to what the bibles say. So, I got the Hornady bible. Lyman and Hornady seem to be in different worlds, as the data between them isn't even close for what I reload. (.223, 9mm, 45-70 Govt, 6.5 CM, .357 Mag) Lyman has charge weights WAY above what Hornady says typically. So, this is when I brought in a 3rd source. I typically use Hodgdon powders, and therefore use their load data. Again, sometimes WAY different than Lyman and Hornady. So, then I got Quickload program. A bit of a learning curve, but I got it and find it to be more accurate in predictions than the bibles typically are.

This is where my question comes in. Using my .223 Rem load data...
Rifle: Ruger AR556 MSR
18" barrel Direct Impingement
1:8 5R rifling
Miculek Comp
No modifications
Lyman data says: test barrel from Colt AR-15 20" barrel, 55gr Jacketed SP and H335 at 24.3gr should be hurling the freedom seed at about 3150fps. Hornady says 23.2gr should get 3100fps, same barrel length. Hodgdon says, 23 grains at just over 3000fps, but their twist is 1:12 and 24" barrel. QL shows it should be doing 2650fps.
MY real data taken by a Chrony shows 23 grains of H335 behind a 55gr Jacketed SP from my 18" barrel 1:8 twist is only doing 2600fps. 80 degree humid Iowa weather. Why? Why the huge difference? I am taking into account for the 2" less barrel length, but not 500fps difference. What am I missing? How can the bibles be so wrong, but QL be so accurate?

My dad must have great confidence in me, as I convinced him to lower his charge weight in his .357 Mag because the velocities were too high. He asked my why the bibles were so different than the real world results. He was really upset he'd been using dangerous load for such a long time. I couldn't answer him. And this has been something I have been trying to figure out for the past 6 years. And now I feel its imperative to find out. Perhaps someone can help me understand. Oh, and BTW, this isn't the only load i've seen these disparities with.

your first error is it is NOT A BIBLE
this is not a SCIENCE, but an ART
start with a very open mind and keep records of everything you try.
change one thing and it is a whole new ballgame.
have fun

 

[WVRJ]

I've seen huge differences in chronographs over the years.A few years ago,I was using a Shooting Chrony Alpha.I have about a dozen rifles and several pistols that I load for and I measured the velocity for each one so I could do drop charts and to help me check for pressure.As has happened to a lot of shooters,I made a mistake and shot the chronograph.I ran across a RCBS chronograph on clearance and bought it.Every load lost velocity,my 22-250 actually showed a loss of 200 feet per second.Chronographs can be off in their readings,especially the cheap ones that have the screens close together.Also,if you're not exactly straight over the center of the screens you can get compromised readings.I still use mine,but I also keep in mind that it's not perfect.I do actual firing for my drop charts out to 1,000 yards and use the amount of drop I actually get vs. what the chronograph and the load data says.

 

[STINGRAY1979]

Welcome to the addiction. What chronograph are you using ? What powder measure system are you using ? How do you store your powder ?

Thanks, Bought the chrony about 5 years ago. Its a Beta Master Chrony. I use the RCBS Charge Master to weigh out most loads. If I'm ever skeptical, I'll use my balance beam scale that I calibrate using a weight set. Store powder in an sealed ammo crate with dessicant.

 

[STINGRAY1979]

your first error is it is NOT A BIBLE
this is not a SCIENCE, but an ART
start with a very open mind and keep records of everything you try.
change one thing and it is a whole new ballgame.
have fun

I don't make errors. lol. My vernacular is not an issue. Theres A LOT of science here. My mind is always open, and hence the reason for my inquiry. I am always having fun.

 

[STINGRAY1979]

I've seen huge differences in chronographs over the years.A few years ago,I was using a Shooting Chrony Alpha.I have about a dozen rifles and several pistols that I load for and I measured the velocity for each one so I could do drop charts and to help me check for pressure.As has happened to a lot of shooters,I made a mistake and shot the chronograph.I ran across a RCBS chronograph on clearance and bought it.Every load lost velocity,my 22-250 actually showed a loss of 200 feet per second.Chronographs can be off in their readings,especially the cheap ones that have the screens close together.Also,if you're not exactly straight over the center of the screens you can get compromised readings.I still use mine,but I also keep in mind that it's not perfect.I do actual firing for my drop charts out to 1,000 yards and use the amount of drop I actually get vs. what the chronograph and the load data says.

Thanks. Yeah, its generally not a good idea to shoot the chrony LMAO

 

[STINGRAY1979]

I have never had a load perform like the reloading manual said it was supposed to...

Ok. So I am not the only one then. Wish my dad had spent the money for a Chronograph, a long time ago. Maybe I would have figured all this out many years ago.

 

[STINGRAY1979]

As mentioned by a bunch of fellows up thread... load data sources will often vary quite a bit from each other. That's one reason why depending upon a single data source is rarely a good idea. The ideal is to find general consensus across multiple load sources. When you don't have consensus... tread extra carefully.

QuickLoad, calibrated carefully as described by Ned Ludd, is an excellent resource. It's particularly valuable because it gives you insight into your chamber pressures. Once you're confident you can model it properly, it can save you a lot of time and components.

That said, something is amiss with what you're describing. When I input your 24.3/H335 load drawn from the Lyman manual, using a Sierra 55gr SPBT, and coming from an 18" barrel such as on your Ruger - all other factors in QuickLoad left at their defaults - it predicts 2902 fps and 45K psi chamber pressure.

View attachment 1345435

I'd suggest not putting too much faith in the results you're getting from your Chrony until you can validate its numbers with another chronograph; or verify it's in the ballpark with a factory load of known performance. And if you're seeing the same 2600ish print from QuickLoad, something is wrong with that. You need to figure out what that is before making load decisions based on it.

Thank you for your response. I'm buying another chrony. Trying ot find a LabRadar. I wanted to buy one about a year and a half ago, and now can't find any.

 

[Coyotefurharvester]

Or shoot a drop check, just need a true 100 yard zero, a couple-5 rounds at 400 yards. The bullet impacts will tell the velocity. If you are not shooting past 300 then your velocity(rifle) doesn't matter, only group size, shape. I rarely check velocity until best grouping load is determined.

 

[Ned Ludd]

Thank you for your response. I'm buying another chrony. Trying ot find a LabRadar. I wanted to buy one about a year and a half ago, and now can't find any.

The message below is from LabRadar's Facebook page. If you're still interested, I'd contact them to make sure the release date for the LabRadar Lite has not been pushed back, then start checking online at various vendors at around 8:00 am, which is when it seems vendors update their online inventory. I purchased the original version several years ago. AFAIK, it has the same features as the new "Lite" version (i.e. no Bluetooth or Mobile App), which is fine because I wouldn't use those anyhow. I would strongly recommend adding the JKL Kinetic trigger (https://jklprecision.com/product/labradar-trigger/), and the magnetic mount (https://jklprecision.com/product/labradar-trigger-magnetic-mount/), assuming these items are fully compatible with the "Lite" version. The extra $50 or so is well worth it in terms of facilitating the use of the LabRadar when there are adjacent shooters at the range.

The key here (IMO) that is often overlooked is that when the group spreads aren't up to snuff, or some other issues interfere with the load development process, recording every piece of data available (including velocity) markedly improves the odds of finding and rectifying the issue. If you don't record such data and have a problem, there is no way to know with certainty what went wrong and formulate a plan on how to fix it. That effectively puts you back at square one with no guarantee anything will go differently (better) the second time around. No one is forced to look at or use the velocity they have recorded, but if it isn't recorded at all, they can't look at it even if they want to. Recording velocity data is a no-brainer IMO. With a chronograph such as the LabRadar, it's a really minimal effort. You don't have to look at it or use it, but it will be there if you ever need it.

 

[209jones]

Every once in a while you will get a gun that is close to book values, but, it isn't very often. Same with factory ammo, had stuff that was as published, had stuff from 100-300ft slower on the same length barrel. And turned around and loaded stuff that was 50-150ft faster than published and zero pressure issues, great brass life too. Way too many variables in how stuff is made, and each piece has an effect.

 

[ebb]

Its the crony, maybe new batteries would help? if there is that much difference it is the crony, or how it is set up.

 

[Rsadams]

Ok. So I am not the only one then. Wish my dad had spent the money for a Chronograph, a long time ago. Maybe I would have figured all this out many years ago.

You can spend tons of money on this stuff... If your not trying to set the world on fire I suggest the pro crono... Not to expensive and it works for me... I dropped mine and sent it back and couldn't be happier with their service...
Buy a box of factory ammo , run it across the crono for data and then it gives you a starting point..... Loading manuals are a reference to start with.... I will once again say I have never had a screaming hot load that was super accurate....