Ramshot Big Game Quickload Help

[NigelM]

Have been working up a load today using Nos 150 ABLR's in 7mm08 using Ramshot Big Game.

According to Ramshots own Load Data 46.2 grains with a 150 Barnes TTSX hits 2782fps ay 60,000 psi, on max. The monolithic bullets usually load a bit lighter than lead core and run slightly higher pressures, so I would expect 58k/59k with the ABLR.

Big Game sits right between H380 and H414/W760 in the burn rate charts. Look at the data for these two powders and you get 45.5 grain max and 46.5 grain max respectively. So the Ramshot data looks right.

Today I worked up to 46.2 grains of Big Game and hit 2770fps with no signs of any pressure, so up to now all makes sense.

However, plug it all into Quickload and everything falls apart. Now I know Quickload is a guide rather than gospel, but it has always been pretty close in the past with R15, H4350, IMR7828 and all the other powders I have used.

I have measured everything, actual case capacity, case length, bullet length, barrel length etc. but it shows a max of 44.3 grains of Big Game giving 2820 fps. Any more powder than that and I'm over pressure and I'm 50 fps off their velocity with a vastly increased load.

To get anything to match I have to reduce the Burn Rate factor of Big Game, which I know is getting into dodgy ground. It's QL burn rate factor is 0.5220.

If you look at H380, the powder above BG in the Burn Rate Charts it has a QL burn rate of 0.4770. Look at H414, just below BG in the charts, it has a burn rate of 0.4529.

Funnily enough, change the burn rate factor of BG to somewhere between these two, I used 0.4700, and all the stars align, with speed at 2770fps and pressure at 55k psi, reflecting what I'm seeing in real life with no pressure signs at all.

Before QL I wouldn't have thought about it. I have no pressure signs and my 46.2 grain load matches the max load in Ramshots reloading data. However, I have never had to change a QL burn rate before and am always a bit suspicious of my findings being more accurate than those who really know what they are doing.

What are the thoughts of the SD QL experts before I go any further? Should I change the burn rate in QL to match my actual results and work from there or not?

 

[Yorric]

I'm not a QL expert by any stretch of the imagination & much as I like using QL, I wouldn't dream of altering any of the powder burn rates in the software.
There are too many variables in the real world to be sure of what you are tinkering with in the digital world.
We mere mortal rifle shooters cannot easily measure chamber pressure - we just see the effects. We can check velocity though & look out for pressure signs.
All we can do is check that QL matches some published data & see if our reloads using the data mirror it to some degree. ---- More than that is getting into the crystal ball Holy Grail world & each one of us has to decide on the risks for ourselves.
Consider batch to batch powder variation. Batch to batch & primer maker/type variations. Temperature at the firing point. Whether you have a "fast" barrel.etc etc.

Happy Christmas

Ian

 

[Laurie]

There may be other factors that vary the actual v computer modeled results, the primary ones being your freebore and inside-barrel dimensions. If the barrel is a bit oversize in its groove and land dimensions compared to nominal CIP or SAAMI ones, QL is always going to give over-high predictions. (You can vary them in the model, but really need to be sure just how your bore measures before changing this sort of thing.)

You say you changed all the variables that you can measure before QL input, but how about COAL? Was the COAL value you input the actual one as loaded, or what it would have been if the bullet was just off the lands? The two are often the same thing, but particularly in factory rifles, some of which come with massively over-long freebores these days, actual COAL (frequently determined by magazine length) is not the same thing as potential COAL.

To explain. Think of a situation such as 7mm-08 where the SAAMI COAL is 2.800-inch maximum. You measure your COAL using a Stoney-Point/Hornady modified case gauge or whatever method you use with your chosen bullet and with it 10 (or whatever) thou' off the rifling the figure you seat the bullet to is 2.800" or less. Well and good and accurate as far as QL goes. Using case volume as measured by water overflow weight, those two factors determine the actual combustion chamber volume when the bullet is fully engaged and that COAL / combustion chamber volume is still pretty well unchanged as pressures approach their peak, the bullet having barely moved.

But! ... say when you use the OAL gauge, the bullet sits far enough out to be beyond magazine length, or as often happens sits outside of the case mouth before touching the lands. You still input actual COAL as loaded, but as the bullet moves out of the case-neck into the lands long before PMax is achieved in this situation, QL will seriously underestimate pressures for any given charge weight. (Conversely it will overestimate PMax for a charge weight that in that particular chamber freebore is longer than the actual COAL being used.)

I have three 7X57s, two of them service Mausers, one a 1950s Beezer sporter. They all have VERY long freebores (as do most 7X57 rifles irrespective of age, make, and model). I cannot seat a 139gn Hornady BTSP in the case-neck in any of them anywhere near touching the lands, and even 150gn bullets are well off the lands at the CIP / SAAMI maximum COAL, but can just be accommodated in these rifles' long magazines seated to a nominally over-long COAL value. In the case of the 139 in particular QL underestimates pressures / MVs substantially in this situation. If I were to load my rounds right up to full service velocities (which I don't anyway for these three old ladies), QL would tell me that I was way over pressure.

FWIW, QL isn't always correct and there are some powders that are plain wrong in the model, unfortunately in the examples that most often affect me directly they are of the type known in my old industry (railways) as 'wrong-side failures', that is give a falsely reassuring result (eg proceed signal aspect when there should be a red / stop indication). Both Reload Swiss RS52 and Viht N160 serially produce higher MVs and pressures than QL predicts IME, so much so that for the former I never use the model at all, simply use Hodgdon's VarGet starting data, the pair being very close in their behaviour, and for the latter set on an estimated 53,000 psi PMax for the heaviest of my initial pressure / function test loads, knowing that will may be as high as 57-59,000 psi in real life. I have seen QL estimate that loads of up to 2gn too high will be fine. Some people are now altering RS52's Ba value in the model by around 10% 'slower' to match real-life results.

As an example of this an N160 load I use in mid-range competition on a regular basis, quite by chance in 7mm-08 too but with a custom chamber that gives 160-168gn match bullets 2.95-3.00" COALs, tells me that even with everything input exactly as it really is, I have a 117.3% fill-ratio,65,920 fps PMax and nearly 100 fps higher MVs than I actually get. There are compressed loads and really compressed loads, and whilst mine is slightly compressed, it is nowhere near a 117% F/R level, nor is it generating over 65,000 psi pressures. So far though, I've found QL to be pretty close to actuals with Ramshot powders.

 

[Southern]

Forget about burn rate and QL. Pay attention to Ramshot.
46.2 gr of Big Game is a pet load of several 7mm-08 shooters, with the bullets seated out to 2.913 inches.

45.0 gr of Big Game for 2,700 FPS is a very accurate load of a friend in his Thompson Center single shot.

Same 46.2 gr charge under a 140-gr seated to 2.810.

 

[Muir]

Forget about burn rate and QL. Pay attention to Ramshot.
46.2 gr of Big Game is a pet load of several 7mm-08 shooters, with the bullets seated out to 2.913 inches.

45.0 gr of Big Game for 2,700 FPS is a very accurate load of a friend in his Thompson Center single shot.

Same 46.2 gr charge under a 140-gr seated to 2.810.

This.~Muir

 

[NigelM]

Thanks Guys.

Muir and Southern, I have gone with the Ramshot data and it is working very well. My issue is that I don't understand why the QL predictions are so wrong.

Laurie, my COAL is 2.815" and yes I am using in in QL. I can't get anything longer in the mag. Freebore is very long at around 2.950", I haven't actually found the exact measurement yet. I can't get anywhere near it so I'm trying to find and accurate load at Max mag length. Perhaps the excessive freebore is responsible, however...

What I can't quite understand is why Ramshot gives 46.2 max load at 59k psi for the 150 grain bullet loaded to 2.760" and QL gives 60k psi for 44.3 grains when all the parameters are the same. I have used QL quite a lot over the past two years on many loads and I have never seen this before.

And if all the Burn rate charts say that Big Game sits between H380 (0.4770 in QL) and H414 (0.4529 in QL) then why is the QL burn rate up at 0.5220 which is very similar to R15?

Just trying to learn a bit more. Thanks for your help.

 

[Laurie]

The burn rate value in QL is what the manufacturer advises to the program compiler. Burn rate is a very tricky item as it is variable depending on application. All the burn rate tells you is how one powder compares to another within the same manufacturer's range (assuming the closed bomb test was done identically for each grade) in a single circumstance.

As a result, it is broadly useful in categorising powders as to possible applications, but can also be misleading at times. Most handloaders place FAR too much weight to this factor.

Both handloading manuals and QL should be treated as guides, starting points only. The benefit of the former is that it involves a SAAMI or CIP spec test barrel and chamber and measures actual pressures. Nowadays. most bullet companies also do a second series of tests using a 'real' (factory) rifle to obtain 'real world' MVs as they are often very different from those obtained in pressure test barrels, usually lower. The downside of the manufacturers' data are that they use a single set of components, and yours may vary from those even though you 'think' you are using the same thing, or something close enough to be treated as the same. That is the published data only apply to that exact set of case make, primer make and model, bullet make and model as well as weight. Speer for instance warns that there are large variations in 243 Win case volumes which in turn affect pressures, that it used Winchester brand brass in all its testing, and states specifically that use of any other make of case invalidates the data in the tables. Many handloaders change case, primer, and bullet make, the only things in common with the as-tested cartridge being powder grade and bullet weight, and think that data-set still applies. It might, or it might not.

QL has all the same problems as published data and a few more being simply a bunch of equations strung together and relying very much on powder manufacturer data accuracy and manufacturing consistency. It does have two great advantages over the published material though - a huge range of cartridges simply not covered at all in the manuals, and within that the ability to massively expand the range of components which can modeled as combinations unlike manuals which are restricted to at best 20 or so. It can also allow a degree of customisation as in things like actual COALs as in individual rifle chamber freebores for those who wish to do this. It can also allow a great deal of desktop modeling to play out different scenarios - more of an issue for the serious long-range target shooter who is trying to juggle internal and external ballistics performance between potential competing cartridges, powders, and bullet models, also considering likely barrel life while at it.

Finally as I keep saying for the benefit of our American friends, all US published manuals are shortly to become heavily devalued for European handloaders thanks to REACH. It is simply no good saying look at a manual when in many cases for older cartridges that aren't upgraded anymore, not a single quoted powder will remain available here, and even in recently tested and published material, 80% of the loads will be useless because of lack of available powders. This has in fact become even worse with the most recent introductions as US bullet makers and others on that side of the Atlantic had a love affair with Vihtavuori propellants for some years, but it has apparently cooled off dramatically. To take Sierra's data for the 6.5 Creedmoor, by definition all very recent, there is a only single Viht load quoted in 10 tables, for Viht N540 with the new 150gn MatchKing. IIRC Hornady 10 edition has no Viht powders in any recently added load ... and so on. Within the Sierra 6.5 Creedmoor tables, to take 123 to 140gn bullets as examples we see:

123 ....... 9 out of 12 powders used are Reach non compliant and are currently disappearing
130 MK ...10 out 14 are non compliant
130 TMK .. 11 out of 14 non compliant
140 ........ 10 out of 15 non compliant

There are replacement powders we use here and which will become much more important as Hodgdon and most IMR grades disappear which aren't available in the US and therefore don't appear in printed manuals at all. Their manufacturers' online loads data is in some cases very limited to applications (cartridges) and/or is frankly of very poor or limited quality. QL becomes a lifesaver for many emerging situations and requests on forums for help from program owners are steadily rising (as I'm sure are program sales too).

 

[Muir]

The burn rate value in QL is what the manufacturer advises to the program compiler. Burn rate is a very tricky item as it is variable depending on application. All the burn rate tells you is how one powder compares to another within the same manufacturer's range (assuming the closed bomb test was done identically for each grade) in a single circumstance.

As a result, it is broadly useful in categorising powders as to possible applications, but can also be misleading at times. Most handloaders place FAR too much weight to this factor..

This is a hugely misunderstood factor in burn rate and should indicate -just by associative reasoning- that when applied to cartridges of different volumes and shapes with varying bullet weights, the burn rate is altered.~Muir

 

[NigelM]

I learn something every time I ask a question on here. Thank you Laurie and Muir.

 

[iain b]

Forget about burn rate and QL. Pay attention to Ramshot.
46.2 gr of Big Game is a pet load of several 7mm-08 shooters, with the bullets seated out to 2.913 inches.

45.0 gr of Big Game for 2,700 FPS is a very accurate load of a friend in his Thompson Center single shot.

Same 46.2 gr charge under a 140-gr seated to 2.810.

45.5 grains of big game gives me 2800 FPS out of my 700. Groups less than an inch and does the job

 

[Southern]

I think the new Alliant powders made in Sweden, RL-16, RL-23, and RL-26, meet the REACH standards, are smaller grains, and offer some high velocities without the temperature sensitivity of some of the other Reloder line. RL-23 would be a powder to try with the 150-gr bullets in the 7mm-08.

 

[Laurie]

I think the new Alliant powders made in Sweden, RL-16, RL-23, and RL-26, meet the REACH standards, are smaller grains, and offer some high velocities without the temperature sensitivity of some of the other Reloder line. RL-23 would be a powder to try with the 150-gr bullets in the 7mm-08.

All Alliant propellants sold in the UK are REACH-compliant Southern. However, we haven't seen a new Alliant grade here in several years, literally none since Re17 (and that has been withdrawn in its Alliant form as it is Reload Swiss RS60 with a different sticker on it).

I keep being told by US friends and correspondents that I really must try this new Alliant grade or the other, Re16 and AR-Comp being good examples. The fact is that Alliant ATK has never gone through the EU certification process for them to get the required 'CE' approval mark. This isn't a cheap process and the long and short of it is that Alliant can sell every 1 or 8lb tin of these propellants in its primary US market without any of the hassle and expense of certifying it for Europe and then physically shipping it here. So Re16, Re23, Re26 are not imported and from what I'm told none is likely to be in the foreseeable future.

The irony of these being European manufactured powders is not lost on us when we can't buy them here. Hodgdon on the other hand has a long-standing commitment that it will CE-proof everything and that nothing is restricted to North American customers, but that effort and expenditure have now been wasted as the EU has moved the goalposts to suit itself and sadly nearly all Hodgdon / IMR brand grades are non-compliant, only a few of the most recently introduced St. Marks Powder manufactured spherical grades and the still being introduced IMR 'Enduron' powders potentially compliant.

 

[Southern]

Since the IMR Enduron powders are supposed to be used in some USGI and NATO ammunition, they are supposed to meet REACH "standards". These Reloder powders, and AR-comp, are supposed to contain none of offending chemicals and, like CFE-223, have a copper fouling resistance. As you say, the EU has moved the bar.