Downsides to "loading down"?

[BurnOut]

Other than losing case efficiency (and therefore burning more powder than necessary for a given velocity), is there any downside to loading a cartridge "cold" (as in, the opposite of "hot")? Think along the lines of 300WM loaded to duplicate the velocity of a .308 Win (given the same projectile).

I'm asking because I am in the planning stages of my next build, and I have a goal of 3000 FPS at the muzzle... and most of the cartridges I look at are either creeping up on that (as in, I might be able to get there), or well over that (as in, 3200 FPS). So I was wondering if it wouldn't make sense to go with the case that I know could get me to my velocity goal, then loading it down/cold/light in an effort to extend barrel life (vs that same cartridge at full velocity), etc...

 

[djarecke]

In your example, a 300WM "loaded down" would now officially be a 308. The bullet only cares about the velocity at which it exits the barrel.

Loading down a node is usually a good way to extend component life at the expense of a few tenths of elevation and wind. My rule of thumb is to go after accuracy and let the velocity end up at a reasonable level for that cartridge and bullet combination.

 

[BurnOut]

In your example, a 300WM "loaded down" would now officially be a 308. The bullet only cares about the velocity at which it exits the barrel.

Loading down a node is usually a good way to extend component life at the expense of a few tenths of elevation and wind. My rule of thumb is to go after accuracy and let the velocity end up at a reasonable level for that cartridge and bullet combination.

Thanks for your response. I understand that in regard to ballistics, all that matters (for a given projectile) is the speed at which it leaves the barrel (and that it has the rotational speed required to stabilize); this can be easily illustrated with subsonic .308 Win compared to subsonic 300BLK. I am more concerned about things like carbon donuts that form in the throat due to low pressure (I don't know if that's a thing, I just pulled it out of my ear as an example), or cases that don't swell up enough to adequately form/seal to the chamber (again, pulled out of my ear to use as an example), or other such issues.

 

[supercorndogs]

Loading down magnum cartridges is very dangerous. You should not go below recommend minimum charges for a magnum. The worry is too little powder will cause a secondary explosion.

 

[supercorndogs]

68.5 of 4831sc with a 208 a max was a good light load, only 2690. I shoot the 200ELD now with 74.5 of 4831sc for 3000fps.

 

[Gunfighter14e2]

Other than losing case efficiency (and therefore burning more powder than necessary for a given velocity), is there any downside to loading a cartridge "cold" (as in, the opposite of "hot")? Think along the lines of 300WM loaded to duplicate the velocity of a .308 Win (given the same projectile).

I'm asking because I am in the planning stages of my next build, and I have a goal of 3000 FPS at the muzzle... and most of the cartridges I look at are either creeping up on that (as in, I might be able to get there), or well over that (as in, 3200 FPS). So I was wondering if it wouldn't make sense to go with the case that I know could get me to my velocity goal, then loading it down/cold/light in an effort to extend barrel life (vs that same cartridge at full velocity), etc...

The flip side is speed an mass are great, but accuracy is final. It matters little how the numbers stack up if you can't put it where it needs to be.

 

[Gunfighter14e2]

Loading down magnum cartridges is very dangerous. You should not go below recommend minimum charges for a magnum. The worry is too little powder will cause a secondary explosion.

I shoot subsonic's out of both 300wm's I own.

 

[BurnOut]

Loading down magnum cartridges is very dangerous. You should not go below recommend minimum charges for a magnum. The worry is too little powder will cause a secondary explosion.

Interesting... is this based on an inadequate case fill? To where the powder may (theoretically) be arranged in the case such that there might effectively be two separate charges? Something that I hadn't considered (though I should have, given my previous example of subsonics) is using a bulkier powder to provide adequate case fill that has a burn rate appropriate to get me the MV that I want.

 

[BurnOut]

The flip side is speed an mass are great, but accuracy is final. It matters little how the numbers stack up if you can't put it where it needs to be.

Agreed on this side of things as well... I'm just trying to meet a down-range energy goal (of my own devising, admittedly). If I don't end up at 3000 FPS exactly, that's fine... but I just want to ensure that I have the flexibility to find a node in that neighborhood without pushing too hard and burning out a barrel in 500 rounds or something.

 

[supercorndogs]

I shoot subsonic's out of both 300wm's I own.

I bet you didn't achieve it with 25 grains of H1000 either. There are appropriate powders and case fills to achieve most of what a person wants.

Whats wrong don't you have a 308?

 

[supercorndogs]

Interesting... is this based on an inadequate case fill? To where the powder may (theoretically) be arranged in the case such that there might effectively be two separate charges? Something that I hadn't considered (though I should have, given my previous example of subsonics) is using a bulkier powder to provide adequate case fill that has a burn rate appropriate to get me the MV that I want.

Yea. mostly. Case fill being the important factor.

 

[Gunfighter14e2]

I bet you didn't achieve it with 25 grains of H1000 either. There are appropriate powders and case fills to achieve most of what a person wants.

Whats wrong don't you have a 308?

Yes in fact 4, but I doubt you do the kind of shooting I do. When we do a woods match, one gun has to do it all, like quietly doing sentry's to 500yds. You shoot a H/speed rd at a sentry target or even shoot a sub rd w/o a can on an your done for the day, mission fail! It's about knowing an using what you have, not what you would like to have. Not everyone owns or shoots like every one else.

 

[supercorndogs]

I see loads in my Hornady Manuel down to 2400 fps with the 300wm and the 208 a max 55-60 grains of powder. 2400 with a 208 is still a pretty heavy 308 load.

 

[Marksman10x]

HODGDON® H4895® REDUCED RIFLE LOADS

For Youth Hunting, Informal Target, and Plinking

__________________________________________________________________________

Hodgdon Powder Company has found that H4895 can be loaded to reduced levels. H4895 was chosen because it is the slowest burning propellant that ignites uniformly in reduced charges. To create reduced loads, the 60% formula is recommended.

Find the H4895 load in the Reloading Data Center for your caliber and bullet. Take the maximum H4895 charge listed and multiply by 60% (.6). The load may

be adjusted up from there to achieve the desired velocity and accuracy.

This works only where H4895 is listed. DO NOT use in a cartridge where H4895 is not shown.

Example: 30-06 cartridge with 125 gr. Sierra SP bullet. Max load shown in the Reloading Data Center with H4895 is 53.7 grains. 53.7 X .6 = 32.2 grains. The shooter begins with this load, and may work up from there to obtain the desired velocity and accuracy for his reduced load.

Call Hodgdon Powder Company if additional information is needed, 913-362-9455.

 

[Marksman10x]

Loading magnum cartridges to slower speeds is not anymore dangerous than any other type of reloading. One just must know what they are doing. And to the OP, you're way overthinking this. If you want to shoot reduced loads in your 300, go right ahead, people have been doing it for decades. Stay within published load data, use common sense, and you will be fine.

 

[Gunfighter14e2]

I see loads in my Hornady Manuel down to 2400 fps with the 300wm and the 208 a max 55-60 grains of powder. 2400 with a 208 is still a pretty heavy 308 load.

Reloading manuals are for new re-loaders, an are heavily lawyer'ed up an for a good reason. They are a guide not a Bible. I have subsonic loads for every weapon I own an well as loads that surpass book max by as much as 300fps, depending the task I'm loading for. You see nothing about duplex or triplex powder loadings and for good reason, yet those loads do allow extreme damage, far exceeding a normal load.

 

[spife7980]

Other than losing case efficiency (and therefore burning more powder than necessary for a given velocity), is there any downside to loading a cartridge "cold" (as in, the opposite of "hot")? Think along the lines of 300WM loaded to duplicate the velocity of a .308 Win (given the same projectile).

I'm asking because I am in the planning stages of my next build, and I have a goal of 3000 FPS at the muzzle... and most of the cartridges I look at are either creeping up on that (as in, I might be able to get there), or well over that (as in, 3200 FPS). So I was wondering if it wouldn't make sense to go with the case that I know could get me to my velocity goal, then loading it down/cold/light in an effort to extend barrel life (vs that same cartridge at full velocity), etc...

3000 fps isnt a very downloaded velocity for a win mag. With a 160-180 its not hot but it certainly isnt a "reduced" load. A 308 will push those same bullets along at 2500-2700 fps.

Nothing at all wrong with not pushing the envelope. I wouldnt load it down to 2600 though just because whats the point? At that point get a 308 instead and save powder.

 

[supercorndogs]

I guess the only disadvantge I see would be, using 55-60 grains of powder to do what you could with 40-45 in a 308.

 

[BurnOut]

3000 fps isnt a very downloaded velocity for a win mag. With a 160-180 its not hot but it certainly isnt a "reduced" load. A 308 will push those same bullets along at 2500-2700 fps.

Nothing at all wrong with not pushing the envelope. I wouldnt load it down to 2600 though just because whats the point? At that point get a 308 instead and save powder.

I just used 300 WM as an example... I'm actually looking at the 7 LRM and possibly downloading it to 280 AI (or maybe 7mm RM) velocity; I just figured that for the purpose of discussion, 300 WM and .308 Win are much more common than either the 7 LRM or the 280 AI.

What I'm trying to figure out is a pair of cases (one in 6.5 mm, one in 7 mm) that share the same bolt face and action length that can get heavy-for-caliber projectiles to whatever accuracy node is closest to 3000 FPS. The idea is for a pair of barrels to be able to swap out on either a TL3 or a Mausingfield. My current thought (though this is subject to change from one hour to the next) is 7 LRM and 26 Nosler.

 

[myronman3]

just follow manuals and you'll be fine. BUT, if it states MAGNUM primers, use them. NO deviations. once you get to a certain point in reduced powder/case volume, pressures can spike.

when in doubt, follow the manual. in fact, ALWAYS follow the manual and you will have a lot of versitility and you'll enjoy handloading for a much longer period of time. i still have both eyes and all ten fingers.

 

[spife7980]

Maybe its just me but all of your goals to me are contradicting one another...


You want a heavy 7mm up to 3000, thats basically what the 7lrm does with normal loads. Loading it down as you inquire about would directly combat with your previous velocity desire. A 26 nosler will push a 140 that fast with a full load.

Cutting your velocity goals by 15-20% and shooting for 280/260 velocities would allow you to load down the 7lrm and 26 nosler but at that point youre just burning up more powder to get the same external ballistics as the small cartridges and no useful benefits in barrel life at the additional cost of tooling up for the exotic cartridge (brass, dies, no on the shelf prefit barrels so thats additional lead time in addition to cost etc).

Now if you had the large gun already and wanted to lessen recoil but couldnt afford a second set up then I would say yeah, get a good recoil pad and lighten up the load. But this looks to be the exact opposite: youre wanting to spend more to achieve less and I dont think anyone will ever be able to reason the cross purposes out.

 

[BurnOut]

spife- from what I've been able to find, it looks like the 7 LRM is seeing 3100-ish out of a 26" barrel with 180 gr projectiles, while 7mm RM seems to be getting 2950-ish out of a 24" barrel... so it seems that with another two inches of barrel, I might be able to push it to 3k. So, what I'm thinking is downloading the 7 LRM by around 100 FPS... instead of pushing the RM hard, I'm in the butter zone of the LRM. Same with the 26 Nosler running 14x grain projectiles... I could go with the 264 WM and maybe push it hard to get there, or I could go with the 26 Nosler which seems to see 3150-3200 at full charge. Soften the load a little bit, and I have plenty of room to speed up if for whatever reason I need it.

I dunno... maybe it's a mental masturbation exercise...

 

[spife7980]

Now that makes a lot more sense to me and it's pretty much what I do with my 3006. I load a 150 gr to 2800 which is a reasonable 308 velocity as well. I only have one revolution on its turret and within that amount of elevation travel the 150 runs right along besides what the heavier would do so I'm really not giving up all that much in terms of tangible benefit. Actually in terms of elevation the 150 goes further in 14 moa than a 180. After that point it completely inverts and the 150 falls apart but I don't plan on shooting anything too far out past 500 with it. And it's what I have and it holds sentimental value so It is what it is.

So going from a big mag to a slightly less big mag works well in my opinion. Going from my 3006 to a 300 sav makes much less sense, it's an ill suited pursuit, and would be the equivalent of going from the 7lrm to a 280 in my mind. To the 7rm level velocities should work well.