Trimmed too short, now what?
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123 Posts
what brand and how many?
if you don't want to bother with them shoot me a PM, i may want them.
if you don't want to bother with them shoot me a PM, i may want them.
To be honest with you, unless you're wanting absolute max accuracy, I wouldn't worry about it. Shoot'em and load them until they finally die from excessive uses. Now, if you're trying to squeeze 0.5 MOA groups out of it, then load them and use them for hunting loads you will not be picking up.
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7,645 Posts
I have done the same thing before when I first started loading for my 308 Winchester, I asked the same question to a reloading guy at the local gun store and he said shoot them and they will grow when you resize. I agree that this will not affect your accuracy unless you are shooting very long distance.
As long as you're not talking a case that headspaces on the case mouth, like the 30 Carbine, it isn't that big a deal to be .015" short. Make sure the headspace is still good (rim to datum line, on the shoulder) and then just load your bullets a little farther out, if that is even necessary.
Keep in mind Hornady is loading several different cases with a shorter trim-to length so they can seat their FTX bullets and still have the rounds cycle in a lever-action rifle. If they can do it, so can you.
Keep in mind Hornady is loading several different cases with a shorter trim-to length so they can seat their FTX bullets and still have the rounds cycle in a lever-action rifle. If they can do it, so can you.
My concern is that they will weigh much less by being shorter, so I won't have an accurate idea of the case volume. An equal concern is that they will grow too much and I might run into unpredictable case life due to case/head separation.
I am keeping these ones separate for my other lots. Thanks for the response.
I am keeping these ones separate for my other lots. Thanks for the response.
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7,645 Posts
The amount that they are short is likely not significant in weight compared to differences in base dimensions and weight. Weigh some of your short cases and compare to others that are not cut short.
The cases will not 'grow too much' unless you have your die set incorrectly and are setting the shoulder back too far. If that were the case, you would see the same effect on cases that were not cut short.
The cases will not 'grow too much' unless you have your die set incorrectly and are setting the shoulder back too far. If that were the case, you would see the same effect on cases that were not cut short.
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39,105 Posts
Look at it this way re: the trimming. You've taken the equivalent of an extra trimming's worth of brass off of them. So, make a note and retire them one trimming earlier than you would otherwise.
Other than that, I would not sweat it.
Other than that, I would not sweat it.
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611 Posts
Shouldn't be a problem. I sometimes re-size .338 WM cases to make .308 Norma cases. This results in a short neck, about what yours is maybe a little more. My rifle shoots 1/2" groups with these cases, so accuracy is not an issue, unless like said before, you are shooting benchrest or something.
It could result in faster throat wear, but I wouldn't think it would be much of an issue unless you are shooting a lot.
You can volume out your short cases, and they will give you an idea of what they should be over the longer ones, but it won't be off that much.
As for case head seperation, a short neck will not affect your case head near as much as a short shoulder in the chamber. As long as your shoulder is where you want it, you shouldn't expect excessive head seperation over your normal brass.
It could result in faster throat wear, but I wouldn't think it would be much of an issue unless you are shooting a lot.
You can volume out your short cases, and they will give you an idea of what they should be over the longer ones, but it won't be off that much.
As for case head seperation, a short neck will not affect your case head near as much as a short shoulder in the chamber. As long as your shoulder is where you want it, you shouldn't expect excessive head seperation over your normal brass.
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4,735 Posts
+1 on what everybody is advising you to do. Go ahead and continue to use them with normal loads. Eventually they will grow some and come closer to minimum OAL specs.
Unless you're loading to the max, it's not a problem. If you are, then back off the charge wweights by a grain or two. As for predicting case head separation, you can visually see this before it happens, a ring will form about 3/8" from the bottom of the case, when you notice this ring, tosss em on the scrap bucket.
i did the same thing with my 375 rum i just loaded and shot them i compared the groups i shot 2 different targets cant remember the range something hot at around 400 they were not as good but still inside a 6 in circle the cases expanded back in 3 loads these loads were shot at max just over 102 gr of imr4831 235 gr bullet i would shoot them but keep them and your normal cases seperated
A .013" shorter trim length shouldn't be a problem. The only negative effect it could have on accuracy, I can see, is if the bullet leaves the case before engaging the rifling. This still wouldn't be all bad since Weatherby seems to do it without issues.
I'd shoot 'em and not even worry about it.
I'd shoot 'em and not even worry about it.
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14,549 Posts
Tom has it right. Back when the M14 was still king at the service rifle matches, a lot of guys would trim the .308's about 0.015"-0.020" short on purpose. The idea was that since those cases grow an average of about 0.005" per firing, they could trim once and never have to trim again within the life of the case (which was usually only 4 to 6 reloadings in those guns). And these were match shooters, so you can see any affect on accuracy was negligible.
Cartridge brass has a density of 8.53 gm/cc. 0.013" of brass tube that is .308" on the inside and is about 0.014" thick will weigh not quite 0.4 grains. That is smaller than the manufacturing difference of one case to the next for all but maybe Lapua or Norma brass. That's 0.047 grains of water capacity and will change your loads by approximately 0.023 grains if you use the same COL. It's a smaller change than you can measure on a standard powder scale.
If you do crimp your bullets in a cannelure, then setting a 180 grain bullet over 4064 back by 0.013" is the equivalent of adding 0.1 grains of powder. It raises pressure about 400 psi and velocity about 5 fps. In other words, again, this is within the normal range of error for loads.
The neck itself grows during resizing. This is because brass flows from the shoulder into the neck when the sizing die squeezes the shoulder back to a shorter position. The excess brass has to go somewhere.
SAAMI has a maximum case length to keep people from jamming the necks into their chamber throats, which can raise pressure dangerously. The minimum exists mainly so that bullet makers know where to put crimp cannelures when their bullets are seated to their design seating depths. So, its mainly an exercise in manufacturing coordination. If you took way, way too much off the neck, say, a tenth of an inch, then you might start to see some difference in bullet grip that could affect start pressure enough that mixing the short and normal length cases together could cause groups to open a bit.
The bottom line is that maximum case length is a safety critical dimension while minimum case length is a non-critical dimension.
It's not relevant if you don't crimp your bullets, as long as you seat to the same COL as you did before, the usable powder space under the bullet will be unchanged, so your loads will be unchanged.
Cartridge brass has a density of 8.53 gm/cc. 0.013" of brass tube that is .308" on the inside and is about 0.014" thick will weigh not quite 0.4 grains. That is smaller than the manufacturing difference of one case to the next for all but maybe Lapua or Norma brass. That's 0.047 grains of water capacity and will change your loads by approximately 0.023 grains if you use the same COL. It's a smaller change than you can measure on a standard powder scale.
If you do crimp your bullets in a cannelure, then setting a 180 grain bullet over 4064 back by 0.013" is the equivalent of adding 0.1 grains of powder. It raises pressure about 400 psi and velocity about 5 fps. In other words, again, this is within the normal range of error for loads.
The growth is governed by the amount of excess headspace. For the .30-06 that's determined by the length from the base to the shoulder of the case, subtracted from the length from the base to the shoulder in the chamber. The growth itself happens when pressure is high enough to stick the case to the chamber wall, then stretch the brass at the junction of the case head and wall to set the head back against the bolt face. It doesn't happen in the neck. (It also doesn't happen in cartridges that operate at pressures too low to stick the brass to the chamber—those operating below about 30,000 psi peak). So, trimming the neck has no effect on that growth.
The neck itself grows during resizing. This is because brass flows from the shoulder into the neck when the sizing die squeezes the shoulder back to a shorter position. The excess brass has to go somewhere.
SAAMI has a maximum case length to keep people from jamming the necks into their chamber throats, which can raise pressure dangerously. The minimum exists mainly so that bullet makers know where to put crimp cannelures when their bullets are seated to their design seating depths. So, its mainly an exercise in manufacturing coordination. If you took way, way too much off the neck, say, a tenth of an inch, then you might start to see some difference in bullet grip that could affect start pressure enough that mixing the short and normal length cases together could cause groups to open a bit.
The bottom line is that maximum case length is a safety critical dimension while minimum case length is a non-critical dimension.
Case VOLUME with the bullet seated is the main concern and what causes pressure problems...it has nothing to do with loaded OAL, per se. I've shot several calibers using the '06 case, some trimmed to as "short" as 2.43" without ANY problems associated with accuracy or pressure as long as the load was within SAMMI specs to begin with.
All you have to do if you DO see accuracy changes...and you WILL most likely with just about ANY change in parameters to a greater or lessor extent, is to adjust your load, bullet seating depth or other parameters that affect accuracy, to bring the load back to your expected level of accuracy. It's done all the time when developing an accurate load.
UncleNick said basically what I was going to say about the miniscule change in EMPTY case volume. Sometime we lock onto things that have very little relevance in actual fact. Leave the "anal retentive activities" to us perfectionists and just enjoy your toy.
I throat almost all my rifles for my prefered bullet so the bullet base is level with the neck base, IF required, so I can get maximum NET bullet seated case volume...I hardly bother with EXACT SAMMI trim length except when I was competing and found a load that worked at a specific trim length...Now I just make sure trim length is uniform, set my trimmer or use Lee trimmers and forget about it...but I DO trim every firing to keep the accuracy level as high as possible...Just as I benchrest prep ALL my ammo...highly argumentive but works for me...just another little "trick" to get optimum performance out of my rifles and ammo.
As usual the requirements for YOUR rifle, ammo, accuracy level, use and equipment, etc, vary greatly...and over time, components and circumstance. Getting all those ducks in a row is part and parcel of the fun of this sport.
Luck
All you have to do if you DO see accuracy changes...and you WILL most likely with just about ANY change in parameters to a greater or lessor extent, is to adjust your load, bullet seating depth or other parameters that affect accuracy, to bring the load back to your expected level of accuracy. It's done all the time when developing an accurate load.
UncleNick said basically what I was going to say about the miniscule change in EMPTY case volume. Sometime we lock onto things that have very little relevance in actual fact. Leave the "anal retentive activities" to us perfectionists and just enjoy your toy.
I throat almost all my rifles for my prefered bullet so the bullet base is level with the neck base, IF required, so I can get maximum NET bullet seated case volume...I hardly bother with EXACT SAMMI trim length except when I was competing and found a load that worked at a specific trim length...Now I just make sure trim length is uniform, set my trimmer or use Lee trimmers and forget about it...but I DO trim every firing to keep the accuracy level as high as possible...Just as I benchrest prep ALL my ammo...highly argumentive but works for me...just another little "trick" to get optimum performance out of my rifles and ammo.
As usual the requirements for YOUR rifle, ammo, accuracy level, use and equipment, etc, vary greatly...and over time, components and circumstance. Getting all those ducks in a row is part and parcel of the fun of this sport.
Luck
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3 Posts
LEE Factory Crimp Die
Hi gents, this is my first post in this forum.
If you're the average shooter I agree you should use them because they headspace on the shoulder and I know my shooting skills and rifle/scope combo would never allow me to notice the difference in accuracy (although I shoot a 308), but someone raised a good point about cartridge headspacing.
My only grain of salt is if you want to crimp and use a set of LEE dies:
Just remember that if you're using a LEE Factory Crimp die to crimp, your neck may be too short for the crimper fingers to press the brass. I would suggest using the bullet seater to roll a crimp.
Hi gents, this is my first post in this forum.
If you're the average shooter I agree you should use them because they headspace on the shoulder and I know my shooting skills and rifle/scope combo would never allow me to notice the difference in accuracy (although I shoot a 308), but someone raised a good point about cartridge headspacing.
My only grain of salt is if you want to crimp and use a set of LEE dies:
Just remember that if you're using a LEE Factory Crimp die to crimp, your neck may be too short for the crimper fingers to press the brass. I would suggest using the bullet seater to roll a crimp.
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