AR Sponsor
Posted: 1/4/2010 1:59:56 PM EDT
| How and why did things like commercial buffer tubes and 1/9 twist come into being? What improvement was trying to be made? Obviously a 6-position stock has 2 more positions than a 4-position. That is at least a perceived advantage (I only use two positions, but that will be the subject of my next thread). What was the intent behind the commercial buffer tube? What did it offer that the original did not? Why 1/9 twist? I'm not saying there is anything wrong with it, I'm just saying that, if 1/7 already did the job, why complicate things? |
|
Quoted:
The military almost went with 1/9, 1/7 was adopted to shoot tracers. 1/9 is generally/was seen as better for shooting stuff like 55grain than 1/7and 99% of civilians shoot mostly 55grain and some 62 and none of the heavier stuff or tracers. No kidding? Never knew that. Thanks for the info, even though I once again somehow managed to post in the wrong forum. I hate computers. |
|
Quoted:
Quoted:
The military almost went with 1/9, 1/7 was adopted to shoot tracers. 1/9 is generally/was seen as better for shooting stuff like 55grain than 1/7and 99% of civilians shoot mostly 55grain and some 62 and none of the heavier stuff or tracers. No kidding? Never knew that. Thanks for the info, even though I once again somehow managed to post in the wrong forum. I hate computers. 1:9 is the correct twist for M855. The (X)M856 tracer bullet ended up exceptionally long because of the requirement that it trace out to 800m... twist rate had to increase to 1:8 to compensate... then the tracer accuracy wasn't sufficient in arctic temperatures to meet whatever specification, so the twist was increased to 1:7. M193 then didn't meet the accuracy spec but this was deemed to be inconsequential. |
|
1:9 for a long time was considered the ideal twist rate for the civilian shooter. You could shoot the light weight varmint ammo accurately, and shoot those really heavy 62 grain rounds just fine.
A good many people didn't believe that 1:7 could shoot the 55 gr ammo accurately. Also there wasn't much by way of 69+ gr ammo. However now its well known that 1:7 shoots just about everything fine, and with the growing availability and popularity of the heavier weight bullets, it is a silly choice not to go with 1:7 for a general purpose rifle. |
|
Quoted: 1:9 for a long time was considered the ideal twist rate for the civilian shooter. You could shoot the light weight varmint ammo accurately, and shoot those really heavy 62 grain rounds just fine. A good many people didn't believe that 1:7 could shoot the 55 gr ammo accurately. Also there wasn't much by way of 69+ gr ammo. However now its well known that 1:7 shoots just about everything fine, and with the growing availability and popularity of the heavier weight bullets, it is a silly choice not to go with 1:7 for a general purpose rifle. I agree. The 1/9 will fire the really light bullets like the 45gr better than the 1/7, and possibly even fire the 36gr bullets fine, but I'm willing to bet that unless they are varmint hunters shooting small animals, more people will be shooting the heavier 70+ grain bullets than the sub 50 grain ones. |
|
Quoted:
How and why did things like commercial buffer tubes and 1/9 twist come into being? What improvement was trying to be made? Obviously a 6-position stock has 2 more positions than a 4-position. That is at least a perceived advantage (I only use two positions, but that will be the subject of my next thread). What was the intent behind the commercial buffer tube? What did it offer that the original did not? Why 1/9 twist? I'm not saying there is anything wrong with it, I'm just saying that, if 1/7 already did the job, why complicate things? Nothing, other than a manufacturing shortcut that results in a weaker connection to the the receiver. |
|
As I said in another thread the AR has become the M1911 of the rifle world. There are a lot of people making parts for AR15’s and making their own interpretation of a better mouse trap. Since the commercial tube seems to be a recognized standard one would think a major player like Colt started it, but this is outright speculation on my part.
As posted by Gamma762 the 1:7 twist was for tracer rounds. As posted by Postal0311 the 1:9 twist was considered ideal for the range of bullets that were commercially available at the time. So in a matter of speaking 1:7 was the complication not 1:9. Also it seems like there was some initial concern about accelerated throat erosion in 1:7 twist barrels. |
|
Quoted:
As I said in another thread the AR has become the M1911 of the rifle world. There are a lot of people making parts for AR15’s and making their own interpretation of a better mouse trap. Since the commercial tube seems to be a recognized standard one would think a major player like Colt started it, but this is outright speculation on my part. As posted by Gamma762 the 1:7 twist was for tracer rounds. As posted by Postal0311 the 1:9 twist was considered ideal for the range of bullets that were commercially available at the time. So in a matter of speaking 1:7 was the complication not 1:9. Also it seems like there was some initial concern about accelerated throat erosion in 1:7 twist barrels. The 1:7 vs. 1:9 twist debate cannot be compared to the commercial vs. mil-spec receiver extension debate. The only reason the commercial receiver extension came about is because it's cheaper to manufacture, and it results in threads that do not fully engage the threads on the upper receiver, thus making it inferior to the mil-spec extension tube, period. |
|
Quoted:
Just trying to give my take on the questions the author of the tread asked. Not trying to compare issues. This is just curiosity not a flame. What exactly is the shortcut that is being taken? Who started the commercial tube? Who is making the tube? It's in the threading. IIRC milspec tubes are machined, and for whatever reason the entire diameter is smaller. The threads are full depth and fully engage the threads in the receiver. The commercial tubes have pressed threads that are shallower even though the tube diameter is larger. They don't fully seat in the threads on the receiver. If you ever get a chance, compare a mil spec tube and a commercial tube (actually receiver extension, but tube is shorter to type) while they are screwed into a receiver, but without the castle nut tightened. The mil-spec tube will not wobble nearly as much as the commercial tube will. |
AR Sponsor