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> Precision long range hunting and shooting
> Long Range 284 WIN
Long Range 284 WIN
@ 06:08 pm (GMT) |
Mark WhitakerNathan, I have read all of this site and your excellent book and I was looking at building a 300 Win Mag or 7mm Practical until I found this Magazine:http://www.alphaindmfg.com./store/index.php?route=product/product&product_id=52 A Mag that fits in a SA Remington and takes 284 win cases with a OAL of 2.965 in. Is this long enough for a 162 gr AMax? I was originally thinking of the 300 WM but as nearly all game in OZ is 90kg or below the 7mm Practical would be better suited. I already has a 375H&H for anything above 90kg. I then researched mags for my 7mm-08 so I can load to my Max AOL of 2.945 in and came across the above site and I will be ordering a Lumley BM and Alpha Type 2 mag for the 7mm-08. I am thinking of starting with a REM 700 SPS SS and rebarrelling it in 284 win or 284 Shehain 28" or 30" long and semi varmint contour to keep the weight manageable and hopefully get 2950 to 3000fpm My other option if it is viable is get a barrelled Barnard SM action is it will only be about $500 more. Also, what are your thoughts about the KRG Whiskey 3 Chassis? Mark PS. Compliments of the season to you and all readers. |
Replies
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@ 10:36 pm (GMT) |
Nathan FosterRe: Long Range 284 WINWith an internal OAL of 2.965", you have to remove 40 thou for smooth feeding as always. This sets the usable OAL at 2.925". At 2.925", the mag box is just long enough to seat the A-Max so that the Ogive bullet body junction is right at the case mouth. Any shorter and you would be getting into trouble. This is not however, the only consideration. You will need to use a no throat reamer, then have the throat reamed to match the magazine. You'll need to check whether your M700 short action will have to be milled to accept the magazine as has to be done when fitting a Wyatt magazine box.Much depends on what you are wanting to achieve Mark. I am not all that into 4lb gun stocks for general hunting. If going this way, it pays to rigid mount the action as I described in the book regarding the AI chassis. Both the Whiskey and AI stocks have V-Blocks and you will be mating a round action to this V shape with the usual potential for vibration. Rigid mounting is the fix. You need to think about how far you are going to carry the rifle and how practical it will be. I can see you getting up to around 15lb with a semi varmint contour barrel. It will certainly be a low recoiling platform and good for competition work. Such a build will have both pros and cons which only you can answer, it is not for me to say otherwise |
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@ 12:13 am (GMT) |
Mark WhitakerRe: Long Range 284 WINThanks Nathan, A 284 opens up the possibilities with this mag. I will be ordering a 308 type 2 in 3 weeks for my 7mm-08 so I will report back on what needs to be modified. I am heading down to the range this Sunday to test the longer rounds I have made up and I have put the Jewell trigger back on, so the groups should get smaller. If I can get the accuracy out of the 7mm-08 and keep the MV at 2750, the 162gr AMax should be good for 950m and 1600fpm, density altitude of 5500ft, "hot and high" on the Atherton tablelands. One of the good things about hunting in the tropics, thin air!As far as the Whiskey 3 chassis and ones like them, I was just curious. They seem to be everywhere and some are at ridiculous prices! |
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@ 03:44 pm (GMT) |
Nathan FosterRe: Long Range 284 WINNo worries Mark. With the 7mm-08, just make sure that you don't load longer than 75mm/2.950" otherwise you will run into concentricity problems. Bullet jump should then be around 2.4-2.5mm or .094 to .098.If the usuable space in the aftermarket mag box is 2.925, you will need to seat to a COAL of 2.925 or 74.3mm. Bullet jump will be around .126" or 3.2mm. Having the bullet a wee bit below the case shoulder is a good thing in this instance because you have not been able to eliminate all of the bullet jump/freebore, the case neck is able to guide the bullet into the lands with optimum concentricity. What I am trying to say is that- sometimes if you adopt a long magazine that gets you close to the lands- but still not close enough to the lands that you are within say 20 thou along with the bullet fully seated in the case neck- in these instances it can pay to go a little bit the other way and utilize the case neck as a guide which effectively increases the bullet jump- even though you already had the bullet boat tail junction sitting flush with the case neck/shoulder junction. In other words, the bullet sits below the case neck, into the shoulder area of the case and bullet jump is around 2.5-3.5mm as opposed to 1.5 to 2.5mm. This is what I have discovered during my own tests. Hard to explain so I hope that makes sense. |
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@ 04:12 pm (GMT) |
Mark WhitakerRe: Long Range 284 WINMy COAL for the 163gr AMax is 74.8mm.I will be testing rounds of 74.7, 74.6, 74.5 and 74.3mm For the loaded 74.7mm rounds, the bottom of the bullet is just bellow the shoulder-body junction and the start of the boat tail is just below the neck-shoulder junction. From what I understand of your explanation above, a lighter shorter projectile would have concentricity problems at 74.7mm, but the Amax would not. Mark |
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@ 04:20 pm (GMT) |
Mark WhitakerRe: Long Range 284 WINThe internal OAL of the Type 2 308 Mag is 2.965" - 75.266mmMark |
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@ 08:40 pm (GMT) |
Nathan FosterRe: Long Range 284 WINYes, a lighter projectile would suffer concentricity problems.When considering internal mag lengths, always remove 40 thou / 1mm from the given length, otherwise ammunition will not feed smoothly if loaded to the full internal length. So if a mag is stated as having an internal length of 2.965", the actual usable space is 2.925". |
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