The material used on RRA barrels is okay. The problem is, they don't always have good control when cutting their chambers
The material used on RRA barrels is okay. The problem is, they don't always have good control when cutting their chambers
The number of folks on my Full Of Shit list grows everyday
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Im building this riffle for 300 meters max. I may have jumped the gun in purchasing this match barrel. Ill find someone that has a use for it and trade for a standard gove profile one. Thanks for all the input from everyone
Definitely spend a little more on the barrel, that is one of the parts I never skimp on.
It's not that you wound up that far afield, without having extensive information on what RRA tends to put out, everything else on paper made sense for what you wanted (1:8 SS barrel with a 'match' chamber should be the ideal answer for having a precise rifle out to 600m). It's just that RRA is known for making relatively bad examples of what otherwise should be awesome, and basically get rewarded for it because few buyers actually run enough rounds through for it to matter.
The other part is that to sell match barrel hardware to people who haven't exceeded the capability of what a boring bone stock chrome lined barrel can do is remarkably easy; the bigger part of the accuracy equation is really the ammunition; and I'd put one of the Ex Lightweight BCM barrels with 77gr handloads and a good trigger as a far more accurate weapon system than anything RRA produces, and the primary objective of that setup is being light, portable, and reliable, not necessarily tack driving.
Since you mentioned the concern for firing quickly, that's the reason people are suggesting looking elsewhere - the Wylde chamber is basically the minimal engineering route to take a slightly lame barrel and make it put out slightly tighter groups without improving the tolerances elsewhere by tightening the chamber - and the reason this is bad because when firing quickly (putting heat into the barrel) it expands and not only increases the OD, but also while expanding the barrel metal makes the chamber ID gets smaller and then the gun stops being able to extract spent cases.
Spending a bit more gets so much more performance on numerous aspects of barrel, if you can find somebody who wants a good barrel for a hobby gun, you can probably find something that suits your needs a bit better.
Last edited by TehLlama; 06-26-14 at 15:38.
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Thank you for taking the time to share that bit of info. That is a great bit that I will kep in mind on tje next purchase
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I do not understand how it may be that "expanding the barrel metal makes the chamber ID get smaller."
If I understood my physics back in college both the OD and the ID of a metal pipe increase with temperature.
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A metal pipe does not inflate like an inner tube because heat is added. It expands everywhere.
Edit:
I have little experience with RRA barrels and no opinion about them.
Last edited by catargadelendaest; 06-27-14 at 08:35. Reason: clarification
Not wanting to derail the thread but I got to say something to stop the misinformation, like catargadelendaest said, when a metal tube is heated the ID and OD both expand. If this were not true heat wouldn't be so good at freeing up metal parts stuck together.
Back on track. OP if you're only going to shoot 300 yards I'd just go with a standard chrome lined barrel and free float it. There are some good threads on here (recently even) about taking stock chrome lined barrels chambered in 5.56 out to 400 yards or more. A member here, TRIDENT82, has some excellent videos of taking SBR's and LW barrels to some impressive distances.
Last edited by Servo; 06-27-14 at 18:59.
Actually, the ID of a cylinder can get smaller with heat for what is known as a "thick walled cylinder". This happens because the material expands linearly with temperature. However, the expansion around the circumference is 6.28 times the expansion along the radius. So the geometry of a cylinder imposes an imbalance between radial and circumferential expansion. This creates an internal force imbalance with the OD in tension and the ID in compression. In this case the hoop stress of the OD is sufficient to compress the ID.
It can also happen under transient conditions when heat is moving from the ID to the OD. In this case the cooler OD compresses the expanding inner portion and the ID shrinks. This is the sort of condition a rapidly fired barrel sees as heat moves from the bore to the OD.
I don't have my engineering books with me to run the numbers on a chamber to see if it is in thick walled cylinder territory. This phemonenon only happens when the ratio of OD to ID is high.
I would suspect that thick match barrels in tiny calibers are thick walled cylinders
Last edited by JiminAZ; 06-27-14 at 20:21.
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