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Thread: A general question about loading down cartridges

  1. #1

    A general question about loading down cartridges

    Hi all,

    I am new to reloading, and I understand that one of the possibilities of reloading is to diminish the quantity of powder, so as to reduce the performance of a given cartridge.
    Does that mean that for a given bore diameter, the more powerful calibers can always be loaded down to produce the same performances as the less powerful ones ?

    For instance, can a 22-250 Rem be loaded down to produce the same ballistics as a .223 or a 22 Hornet ?

    Or can a 7 RM be loaded down to the performances of a 7x64 or a 7-08 ?

    What are the limits of loading down cartridges ?

  2. #2
    The most accurate handloads are usually slower than factory loads, but I think it is/might be dangerous to use too little powder in a cartridge case.

  3. #3
    The general answer is, "Yes", you can download cartridges a notch. In fact, often some of the most accurate normal loads are not at top power. A really good 7mm RM load may be the same MV as a really good 7x64 load. Just look at the Nosler load pages for 150-gr loads of the .280 Rem and 7mm Rem Mag, for example.

    But beware! You cannot go much below the starting loads of many powders, without danger of a secondary detonation of very high pressure.

    If you want to make really mild load, you need to use one of the few powders made for that purpose. H-4895, for example can be reduced down close to 60% of the maximum load, and the velocities fall in a linear slope matching the loads. An 80% load of H-4895 is usually a good mild load.

    http://www.hodgdon.com/PDF/H4895%20R...le%20Loads.pdf

    http://www.hodgdonreloading.com/relo...w-recoil-loads

  4. #4
    Quote Originally Posted by Southern View Post
    The general answer is, "Yes", you can download cartridges a notch. In fact, often some of the most accurate normal loads are not at top power. A really good 7mm RM load may be the same MV as a really good 7x64 load. Just look at the Nosler load pages for 150-gr loads of the .280 Rem and 7mm Rem Mag, for example.

    But beware! You cannot go much below the starting loads of many powders, without danger of a secondary detonation of very high pressure.

    If you want to make really mild load, you need to use one of the few powders made for that purpose. H-4895, for example can be reduced down close to 60% of the maximum load, and the velocities fall in a linear slope matching the loads. An 80% load of H-4895 is usually a good mild load.

    http://www.hodgdon.com/PDF/H4895%20R...le%20Loads.pdf

    http://www.hodgdonreloading.com/relo...w-recoil-loads
    I have heard this since I was in knickers yet never saw it.
    I remember some years back, the H.P.White Laboratory tried to induce "detonation" in their Lab and was unable to cause the phenomenon. They initially did their tests with light loads in a 38 Special, but later they did the tests in a 30-06 at the behest of Wm.Davis of the NRA technical staff, himself a ballistician. I believe the lab deduced that the placement of a very small charge of slow burning powder lying longitudinally in the bottom of the case caused 'plugging' of the bore as the projectile was driven into the leade by the primer ignition, followed by the fast rise in pressure from the burning of the powder. IIRC is was difficult to make happen. As a side line to the account, one or two cases were investigated by H.P. White where 'detonation' had supposedly happened in the field but were judged to be shooter error: One a double charge of fast burning powder, the other a single light charge of fast burning powder behind a cast bullet that was too large in diameter for the case/chamber combo and the rifle blew up. (a 1917 Enfield) I personally witnessed a shooter firing his 20 Tactical and getting a very low point of impact, smokey cases, and dismal accuracy. He fired 20 rounds, maybe? Returning to my house we found that he'd misread my scale and loaded 13.5 grains H335 instead of 23.5. This represents a 43% under load. When i was a kid guys shot small charges of surplus H4831 behind a tuft of Kapok for cast bullet loads. Some powders like H-110/Win296 do warn against reducing charges in some applications, but in general, I believe "detonation" is more theoretical than inevitable.

    That said, just reducing a powder charge will probably cause erratic accuracy. Powders designed for the task like H4895 and Trail Boss are solidly the way to go.~Muir

  5. #5
    Quote Originally Posted by Southern View Post
    The general answer is, "Yes", you can download cartridges a notch. In fact, often some of the most accurate normal loads are not at top power. A really good 7mm RM load may be the same MV as a really good 7x64 load. Just look at the Nosler load pages for 150-gr loads of the .280 Rem and 7mm Rem Mag, for example.

    But beware! You cannot go much below the starting loads of many powders, without danger of a secondary detonation of very high pressure.

    If you want to make really mild load, you need to use one of the few powders made for that purpose. H-4895, for example can be reduced down close to 60% of the maximum load, and the velocities fall in a linear slope matching the loads. An 80% load of H-4895 is usually a good mild load.

    http://www.hodgdon.com/PDF/H4895%20R...le%20Loads.pdf

    http://www.hodgdonreloading.com/relo...w-recoil-loads
    Southern, Glad you flagged the H4895 for the op. I had a go with reduced loads using the 60% rule I could have gone down to 24 grn from a maximum load of 40gr ie; 7mm-08; 150grn Sierra MKBT 40.5 grn H4895.

    I stopped at 30grn 2,075 fps because it was getting a bit smoky,Ok for plinking.

    FYI; 35grn 2,462 fps, 38grn 2,600fps, 40grn 2,728 fps.

    Your comment with regard to low loads, imho should be listened to. New reloaders and old, can't check too much.

    A good way to reduce recoil is fit a decent Mod. jc

  6. #6
    Thanks all for your very interesting input.

    That said, just reducing a powder charge will probably cause erratic accuracy. Powders designed for the task like H4895 and Trail Boss are solidly the way to go.~Muir
    Would that erratic accuracy be caused by the barrel twist rate not adapted to slower speeds ?


    In theory, I was wondering if, for a hunter who reloads and needs to acquire a rifle of a given bore diameter, the logical choice would be the most powerful caliber, because it would allow also to reproduce the same performances of the less powerful ones. (to reduce recoil, muzzle blast, and preserve venaison and skin/furs)


    Practically, I hunt roe deer with a .222 Rem (legal here in France), and predators and small game with both .222 and .22 Hornet rifles. I appreciate the 22 Hornet for its low report, and the preservation of venaison (hares) and furs.
    I would like to know whether downloading the .222 would enable me duplicate the performances of the .22 Hornet while keeping a good accuracy ?

    I hunt also big game with a 7X65R, and wonder whether it can be downloaded to the performances of a slow 7x57R with good accuracy ? (to reduce impact on venaison)

  7. #7
    Erratic accuracy (more properly erratic ballistics as pressures and velocity spreads become excessive) is due to two causes. The primary cause is running the cartridge at too low pressures for the powder type to burn efficiently and consistently shot to shot; secondly reducing the charge fill-ratio too much, and its corollary increasing the amount of airspace in the case. Most cartridges perform at their best with a powder that provides full working pressures with a 90% plus fill-ratio, and it is generally regarded as undesirable to drop below 80% in larger rifle cartridges with 'normal' rifle powders especially with slow burning types.

    The low charge / 'detonation' issue eventually became accepted after the many 'red herrings' of broken rifles caused by more common mistakes such as using the wrong powder or charge were weeded out and discounted. It's almost entirely confined to large case over bore capacity numbers such as the larger magnums from .300 Win Mag and upwards allied to an over-low charge of the very slow burning powders they employ. Look at most loading manuals' data for the Weatherby Magnums etc and you'll find the starting load involves a smaller % weight reduction over the maximum than applies to most other smaller cartridges with an injunction under each page of tables not to reduce the starting load any further. Even there, doing so would mostly just produce erratic loads not dangerous ones unless taken to extremes.

    The normal practice in working up reduced loads with a conventional single-based rifle powder is to run them with a grade that has one, sometimes two steps faster faster burning rate than those normally employed, also to use powders which have a reputation for being easily ignited which in this bracket normally means single-base tubular types. These characteristics provide more consistent pressures. H4895 meets both criteria for larger cartridges such as .30-06 that would normally use powders whose burning rates are in the 4350 / Viht N150 or even 4831 / Viht N160 bracket. The fill-ratio drops, but the powder's burning characteristics overcome that and it'll burn happily at 40,000 psi or even less albeit sometimes very dirtily. Going back by several editions of the Speer reloading manual to the 1980s and earlier, the compilers inserted a single low-velocity jacketed bullet load for many popular cartridges. They nearly all used IMR-4198 powder in numbers like 308 Win, a powder whose burning rate normally sees it employed in the 222 Rem or low pressure large bore numbers like 45-70.

    Ball powders should never be seriously downloaded as they are usually hard to ignite and need high pressures to operate efficiently. Very, very fast burning double-based powders such as pistol types operate very differently in the cartridge case from rifle powders and are designed to burn consistently despite often taking up a small amount of the available space. They can be used in rifle cartridges, but with lead bullets there being risks with jacketed types. In either event, doing research and knowing what you're about is a good idea.

    Then, there are powders that have been expressly developed to provide low pressures and velocities safely in rifle cartridges with jacketed bullets. The old IMR SR4759 was developed by Dupont to a US DoD contract specification just for this purpose to simulate extreme range terminal ballistics in short-range testing with the 30-06 then the 7.62mm. The old pre Western Powders AA-5744 was likely developed for similar reasons and gained a reputation for excellent performance in large bore BPCR cartridges where it would simulate the (low) pressures and velocities of a case-full of black powder and also worked well in reduced loads in other cartridges being designed to burn consistently at a relatively low pressure. The IMR powder was withdrawn some years back and 5744 hasn't been available that I've seen since Accurate Arms changed ownership. However, 5744 was made by Explosia in the Czech republic and it is still listed as a European Lovex brand powder whose products are still imported ionto the UK in limited quantities. Its Lovex name is DO60, Here's what Explosia says about it:

    RIFLE POWDERS
    S040
    High density, single base, tubular propellant suitable for .22 Hornet
    and .30 Carbine cartridges and for other small shotguns. Also usable
    in high capacity handgun cartridges.

    D060
    High density, double base, tubular propellant similar to Accurate
    5744 designed primarily for .45-70 Government, .45-120 , and .50-90 Sharps cartridges and for reduced loads in all calibres rifles.

    So, it may be possible to get hold of it. As mentioned, IMR Trail Boss is a specialised double-based 'fluffy' powder originally developed to produce low velocity low pressure loads in lead-bullet revolver cartridges that duplicated the performance of tiny charges of powders like Bullseye and Red Dot, but filled cases and made it impossible to use double or triple loads. This was for 'Cowboy Action' shooting where lead bullets and low MVs are mandatory. It has since turned out to be a great powder for reduced rifle cartridge loads especially with lead bullets but also some use with jacketed types and like 5744 for the large bore black-powder numbers. It's so bulky, it's sold in 9-ounce lots, that being all a standard Hodgdon / IMR 1lb bottle will hold. It was available in the UK, but I don't know if supplies have held up during the recent US shortages and problems in getting Hodgdon powders here. Vihtavuori also produced a Cowboy Action propellant N32C Tin Star that isn't anything like as bulky as Trail Boss and didn't catch on as well, but could also likely be used in some downloads. I'm not sure if it's still available.

    For a downloaded 222 looking for Hornet MVs, Trail Boss is the obvious candidate. 7.5-8gn is a full case of this stuff and QuickLOAD predicts 8gn gives a 50gn Sierra SP 2,042 fps at 32,000 psi, but you'd look to start well down at 4 or 5gn charges and work up. 5gn takes up two-thirds of the case space and is predicted to give the 50gn 1600 fps at a mere 16,000 psi but still produce a 100% charge burn.

    For 7X65R H4895 would likely work well using the previously described formulae. QuickLOAD says 43gn under a 140gn Sierra produces 2691 fps at around 43,000 psi. 33gn Lovex DO60 is predicted to produce 2628 fps at 46,000 psi and for really light work, 19gn Trail Boss (full case load) a mere 1790 fps. Both types are shown as giving 99-100% charge burns in a 24-inch barrel.

    These are all QuickLOAD simulations, not field-tested loads, but give an indication of what might be possible - so treat them with extreme caution. It'd be interesting to see what people come up with. I'm sure there is a lot of experience around in downloaded 222 Rem loads as the little cartridge is simply made for this sort of experimentation in a safe manner if done sensibly.

  8. #8
    I've never tried to download cases but a friend used to do it all the time in his .223 and .375.
    He used very fast powders in the .223 behind cast gas checked projectiles against rabbits. Pistol powders.
    I've no idea what he used in the .375 but he did load gas checked cast bullets in it at very stiff loads. Boy they hurt! I saw a roo hit by one at 300m+ and it didn't half leave a mess.

  9. #9
    Quote Originally Posted by Laurie View Post
    Erratic accuracy (more properly erratic ballistics as pressures and velocity spreads become excessive) is due to two causes. The primary cause is running the cartridge at too low pressures for the powder type to burn efficiently and consistently shot to shot; secondly reducing the charge fill-ratio too much, and its corollary increasing the amount of airspace in the case. Most cartridges perform at their best with a powder that provides full working pressures with a 90% plus fill-ratio, and it is generally regarded as undesirable to drop below 80% in larger rifle cartridges with 'normal' rifle powders especially with slow burning types.

    The low charge / 'detonation' issue eventually became accepted after the many 'red herrings' of broken rifles caused by more common mistakes such as using the wrong powder or charge were weeded out and discounted. It's almost entirely confined to large case over bore capacity numbers such as the larger magnums from .300 Win Mag and upwards allied to an over-low charge of the very slow burning powders they employ. Look at most loading manuals' data for the Weatherby Magnums etc and you'll find the starting load involves a smaller % weight reduction over the maximum than applies to most other smaller cartridges with an injunction under each page of tables not to reduce the starting load any further. Even there, doing so would mostly just produce erratic loads not dangerous ones unless taken to extremes.

    The normal practice in working up reduced loads with a conventional single-based rifle powder is to run them with a grade that has one, sometimes two steps faster faster burning rate than those normally employed, also to use powders which have a reputation for being easily ignited which in this bracket normally means single-base tubular types. These characteristics provide more consistent pressures. H4895 meets both criteria for larger cartridges such as .30-06 that would normally use powders whose burning rates are in the 4350 / Viht N150 or even 4831 / Viht N160 bracket. The fill-ratio drops, but the powder's burning characteristics overcome that and it'll burn happily at 40,000 psi or even less albeit sometimes very dirtily. Going back by several editions of the Speer reloading manual to the 1980s and earlier, the compilers inserted a single low-velocity jacketed bullet load for many popular cartridges. They nearly all used IMR-4198 powder in numbers like 308 Win, a powder whose burning rate normally sees it employed in the 222 Rem or low pressure large bore numbers like 45-70.

    Ball powders should never be seriously downloaded as they are usually hard to ignite and need high pressures to operate efficiently. Very, very fast burning double-based powders such as pistol types operate very differently in the cartridge case from rifle powders and are designed to burn consistently despite often taking up a small amount of the available space. They can be used in rifle cartridges, but with lead bullets there being risks with jacketed types. In either event, doing research and knowing what you're about is a good idea.

    Then, there are powders that have been expressly developed to provide low pressures and velocities safely in rifle cartridges with jacketed bullets. The old IMR SR4759 was developed by Dupont to a US DoD contract specification just for this purpose to simulate extreme range terminal ballistics in short-range testing with the 30-06 then the 7.62mm. The old pre Western Powders AA-5744 was likely developed for similar reasons and gained a reputation for excellent performance in large bore BPCR cartridges where it would simulate the (low) pressures and velocities of a case-full of black powder and also worked well in reduced loads in other cartridges being designed to burn consistently at a relatively low pressure. The IMR powder was withdrawn some years back and 5744 hasn't been available that I've seen since Accurate Arms changed ownership. However, 5744 was made by Explosia in the Czech republic and it is still listed as a European Lovex brand powder whose products are still imported ionto the UK in limited quantities. Its Lovex name is DO60, Here's what Explosia says about it:

    RIFLE POWDERS
    S040
    High density, single base, tubular propellant suitable for .22 Hornet
    and .30 Carbine cartridges and for other small shotguns. Also usable
    in high capacity handgun cartridges.

    D060
    High density, double base, tubular propellant similar to Accurate
    5744 designed primarily for .45-70 Government, .45-120 , and .50-90 Sharps cartridges and for reduced loads in all calibres rifles.

    So, it may be possible to get hold of it. As mentioned, IMR Trail Boss is a specialised double-based 'fluffy' powder originally developed to produce low velocity low pressure loads in lead-bullet revolver cartridges that duplicated the performance of tiny charges of powders like Bullseye and Red Dot, but filled cases and made it impossible to use double or triple loads. This was for 'Cowboy Action' shooting where lead bullets and low MVs are mandatory. It has since turned out to be a great powder for reduced rifle cartridge loads especially with lead bullets but also some use with jacketed types and like 5744 for the large bore black-powder numbers. It's so bulky, it's sold in 9-ounce lots, that being all a standard Hodgdon / IMR 1lb bottle will hold. It was available in the UK, but I don't know if supplies have held up during the recent US shortages and problems in getting Hodgdon powders here. Vihtavuori also produced a Cowboy Action propellant N32C Tin Star that isn't anything like as bulky as Trail Boss and didn't catch on as well, but could also likely be used in some downloads. I'm not sure if it's still available.

    For a downloaded 222 looking for Hornet MVs, Trail Boss is the obvious candidate. 7.5-8gn is a full case of this stuff and QuickLOAD predicts 8gn gives a 50gn Sierra SP 2,042 fps at 32,000 psi, but you'd look to start well down at 4 or 5gn charges and work up. 5gn takes up two-thirds of the case space and is predicted to give the 50gn 1600 fps at a mere 16,000 psi but still produce a 100% charge burn.

    For 7X65R H4895 would likely work well using the previously described formulae. QuickLOAD says 43gn under a 140gn Sierra produces 2691 fps at around 43,000 psi. 33gn Lovex DO60 is predicted to produce 2628 fps at 46,000 psi and for really light work, 19gn Trail Boss (full case load) a mere 1790 fps. Both types are shown as giving 99-100% charge burns in a 24-inch barrel.

    These are all QuickLOAD simulations, not field-tested loads, but give an indication of what might be possible - so treat them with extreme caution. It'd be interesting to see what people come up with. I'm sure there is a lot of experience around in downloaded 222 Rem loads as the little cartridge is simply made for this sort of experimentation in a safe manner if done sensibly.


    Laurie,

    I have no experience with 222 recipes but I thoroughly enjoyed your informative post.

    Perhaps an inexperienced reloader should keep it simple with a good reloading book and a helper until all the boxes are ticked.

    There was a very good (long) report by the NRA of an incident with a Krag-Jorgensen 6.5x55 at Bisley in 2014. Not sure of the technology to download it. I am sure it will be easy to find and although there was no definite ruling on the true cause, it is well worth the read if it has not been on here before.cheers,jc

  10. #10
    Quote Originally Posted by Highlandsjohn View Post
    Laurie,

    I have no experience with 222 recipes but I thoroughly enjoyed your informative post.

    Perhaps an inexperienced reloader should keep it simple with a good reloading book and a helper until all the boxes are ticked.

    There was a very good (long) report by the NRA of an incident with a Krag-Jorgensen 6.5x55 at Bisley in 2014. Not sure of the technology to download it. I am sure it will be easy to find and although there was no definite ruling on the true cause, it is well worth the read if it has not been on here before.cheers,jc
    Does that bring back memories!
    When I was young I had a terrible time with a 6.5x55 Krag Jorgensen. No matter what I loaded I flattened primers badly. I finally called my uncle, a good gunsmith with lots of experience, and he said "Slug your bore." When I did I found that it was .2628" and the lot of bullets I had were .2643 inches. He said it wasn't the first time he'd seen this problem.~Muir

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