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Posted: 12/23/2013 5:35:50 PM EDT
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lets say you have 100 pcs of 223 brass that your shooting out of an ar that is set up for cqb type work, could you load all 100 rounds, shoot them to fire form them then just neck size the brass only and not fl size them ? if not why not ? what about for a precision semi auto 308 ar ? would the gun still cycle fine ? |
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Quoted: lets say you have 100 pcs of 223 brass that your shooting out of an ar that is set up for cqb type work, could you load all 100 rounds, shoot them to fire form them then just neck size the brass only and not fl size them ? if not why not ? what about for a precision semi auto 308 ar ? would the gun still cycle fine ? FL resize every loading.
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Yes and no on the probability of a jam. It depends.
For a bolt rig, the chamber dimensions are not all that different, but the forces of manual feeding and loading are more forgiving. For a semi-auto to be reliable, the bolt must not only feed the round but the bolt has to feed well enough to rotate closed. If there are any extra sources of friction or bounces the bolt may not close. On a bolt gun, the feed isn't as violent and there is no dependency on springs or momentum to close. If the operator thinks he isn't being destructive, he will add force and torque till the loading cycle is complete. If that same round hangs up in a semi-auto in a combat situation, you could be dead before you realize you need to push on the forward assist. For many reasons, chambers for reliable semi-auto rigs will tend to favor reliable operation over accuracy. In a bolt gun, there would still be a noticeable difference between a field gun chamber and a benchrest chamber by the same token. The possibility of a slight source of friction, dirt, or small defect that prevents feeding is going to ruin your day if your field bolt gun is as tight as a benchrest rig. The semi auto is just taking the same behavior a step farther because it happens much faster and more violently without a human in the loop for feedback. Real testing shows that if we make automatic chambers too tight, we quickly get reliability problems. The ammo also needs to be considered part of the system. If you allow your ammo to get any larger than what the designers were expecting, you may or may not cross the line. I became part of a team that solved many of these issues for weapon systems that had to be very reliable. We didn't depend on luck. |
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Quoted:
Yes and no on the probability of a jam. It depends. For a bolt rig, the chamber dimensions are not all that different, but the forces of manual feeding and loading are more forgiving. For a semi-auto to be reliable, the bolt must not only feed the round but the bolt has to feed well enough to rotate closed. If there are any extra sources of friction or bounces the bolt may not close. On a bolt gun, the feed isn't as violent and there is no dependency on springs or momentum to close. If the operator thinks he isn't being destructive, he will add force and torque till the loading cycle is complete. If that same round hangs up in a semi-auto in a combat situation, you could be dead before you realize you need to push on the forward assist. For many reasons, chambers for reliable semi-auto rigs will tend to favor reliable operation over accuracy. In a bolt gun, there would still be a noticeable difference between a field gun chamber and a benchrest chamber by the same token. The possibility of a slight source of friction, dirt, or small defect that prevents feeding is going to ruin your day if your field bolt gun is as tight as a benchrest rig. The semi auto is just taking the same behavior a step farther because it happens much faster and more violently without a human in the loop for feedback. Real testing shows that if we make automatic chambers too tight, we quickly get reliability problems. The ammo also needs to be considered part of the system. If you allow your ammo to get any larger than what the designers were expecting, you may or may not cross the line. I became part of a team that solved many of these issues for weapon systems that had to be very reliable. We didn't depend on luck. thanks for setting me straight... i knew neck sizing was not a good idea i just wanted to know the who what when where and the why of the situation |
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Chambering is the key. Many bolt action designs have ramped locking lugs. This allows the lugs to start engaging just as the bolt starts to close. Once started the bolt handle acts like the handle on a wrench. So if you have a round that is what we call a little snug it can often be chambered because of this cam action and bolt torque.
Semi-autos have none of this except for the lead in ramps on the lugs. There are people who neck only size for their semi-autos but by no means is it a "size and go" operation. I do it for one of my mil-surp rifles but I test fit every case before loading it. Its very time consuming. The reason I do it is even more complicated so I won't go there. |
| The pressure level in an AR or any other Semi / Full Auto weapon is fairly high when the case is being extracted. So the case body expands while it is being extracted. It isn't a lot but it is enough to cause chambering issues even in the rifle it was fired in. With a bolt action rifle, you cannot cycle it fast enough to cause the case to expand larger than the chamber after firing. |
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Quoted:
The pressure level in an AR or any other Semi / Full Auto weapon is fairly high when the case is being extracted. So the case body expands while it is being extracted. It isn't a lot but it is enough to cause chambering issues even in the rifle it was fired in. . ^^^This^^^ Here is a good read on loading for semi-autos. http://www.exteriorballistics.com/reloadbasics/gasgunreload.cfm |
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Bolt guns have more leverage to pull tight cases out, very different than a semi auto. Quoted:
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i kind of figured this... but why bolt guns and not semi autos... thats what i want to know, if a stuck case can happen in a semi cant it happen in a bolt gun The problem is getting them IN, not out. |
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I loaded .30-06 cases with .308 dies for over 20 years, partial neck sizing only.
I've loaded and fired many .30-06 cartridges this way through a Remington 742 and it was never a problem, unless I wanted to manually extract a unfired cartridge, which took a bit of effort. I finally bought a set of .30-06 small base dies. I recommend full-length resizing for semi-auto rifle. Small base dies are recommended, but not necessary. |
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Quoted:
I loaded .30-06 cases with .308 dies for over 20 years, partial neck sizing only. I've loaded and fired many .30-06 cartridges this way through a Remington 742 and it was never a problem, unless I wanted to manually extract a unfired cartridge, which took a bit of effort. I finally bought a set of .30-06 small base dies. I recommend full-length resizing for semi-auto rifle. Small base dies are recommended, but not necessary. LOL, I see I'm not the only one. I neck size my 7.5x54MAS with a 300 Rem SAUM Neck Size die. This ammo is for the semi-auto model 49-56. As I wrote above, I do test fit each one before loading. The funny thing is this goes against all the ""warnings"" in this thread and works very well. I got 5 cycles with my lot of about 75 cases before having to do a partial sizing with the full length die. BTW: I can easily unload a chambered round at any time too. I guess it just must be a fluke eh? Don't take this wrong. I am not advocating the practice of neck only sizing for auto loaders and I have a very good reason to do it with this particular rifle. I'm just pointing out the fact that these so called rules are really just good sound advice but are not etched in stone rules. You really don't know how some things will work unless you try them. Knowing the possible drawbacks though is a good thing too. |
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