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Posted: 11/27/2007 9:53:17 AM EDT
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I have an older White Oak 1-10 Moly barrel with a standard SAAMI chamber. Is it even worth the time and funds to have the chamber reamed to the "Improved SAAMI" spec? This barrel will eat what I am currently rolling off my bench. Currently shoots 3/4" to 1 1/4" depending on me the operator. I have a new Ko-tonics also, just want to bring this one up to date as possible and as a more reliably backup. |
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If you are not pushing the loads it should be more accurate than the #2 except, Hornadys bullets like the Vmax or the 115 hp blems that midway was selling have to seat deep to keep the bullet out of the lands. On the 115 hp you cannot use the cannalure at the case mouth. IMO if you shoot factory loads or don't push your reloads, leave it. |
How deep? My Vmax Col is 2.260 and my 2715's are at 2.250. Should I be shorting up on the Col. My SSA SMK's mearure at 2.230 More hints please. |
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The Saami throat is .050-.060 in front of the case mouth. So you want the tangent of the ogive(where the body of the bullet .277 drops to .276) at .030-.040 in front of the case mouth depending on how long the case is. I do not have a reamer drawing with me so I can't give you an exact dim from the rim. Most bullets are accurate when set .015- .020 from the lands. If you seat the bullet out to far you will stuff the bullets into the lands and it will drive up the starting pressure and you will get flat primers or swipes(shiny half-moons) on the bottom of the case, those are both signs of high pressure. To complicate things a Vmax is a secant ogive and shoots better when stuffed into the lands. If you use a moderate load that may be ok but, it is not a good idea in a gas gun. Does anyone want to jump in here a give a readers digest version? 
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I dug around a bit an found this" Except for a good magazine fit, the total length is not important. It is important to accurately measure the overall length of your cartridges from the ogive, because this is how you determine the best seating depth and OAL. " I am getting a clearer picture now. I will have to measure this on both my barrels. |
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This is just my opinion no absolutes. What I started out thinking was it comes down to do you tend to load your round to the higher end? Then I thought of the fact you also have a Ko-tonics Long throat barrel. Also what it is with the different bulllets Constructor is mentioning is where along the bullet does it get to its full diameter and the angle used to arrive there and to its end. The further from the tip the longer you have to load them as in the V-max. You end up with the exact opposite problem with the MK in that max area comes so soon with a longer tail behind it, you end up buring it in the case to keep it off the lands. I would vote for increasing the throat an addition .020 -.030 (DMR Throat) basically you want to increase it so that the majority of bullet when seated just shy of mag length max will have them @ .010 off the lands. This is what Constructor has done in designing the DMR chamber along with tightening up some other dimensions as well. But you can't fix that as you can't add metal back. The main reason I am for the increasing the throat is you also have a Ko-tonics barrel and it would be nice to be able to load rounds that work well in both without having to change thing up drastically. You have a better chance of finding a round that works well in both if you increase the throat on the WOA barrel. It will allow you to seat bullet in them both the same as the limiting factor will be mag length for both. It will also relieve some of the pressure from having a 10:1 twist so you can load it hotter maybe not as hot as Ko-tonics but closer. But if your happy let it be. As far as the V-max bullet design is concerned. It just was never really meant for a gas gun it was designed for bolt guns. With bolt guns you usually start .005-.010 off the lands then move in from there or the reverse. You can't do this in a gas gun as its spring power that cycles the gun. Also the bolts on bolt guns are much stronger and the chambers can be made tighter to support the case better allow much higher pressures. A suggestion get Precision Shooting's Reloading Guide I had been reloading for awhile and I learned quite a bit from it. IIRC it has a section on AR specifically which will help. Tim Welter |
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