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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Independent Study: LRH calibres - 7mm WSM vs 300 RUM vs 338 LM
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<blockquote data-quote="Haagen Dazs" data-source="post: 632778" data-attributes="member: 42602"><p><strong>338 Norma Mag? How much is too much?</strong></p><p></p><p>To answer some questions, I'm not going to compare handguns because it's a big no-no up here in Kanukistan. I'm also just looking at long range chamberings and basing everything of a suggested formula that may or may not be accurate for certain bullet/velocity combos. </p><p></p><p></p><p>Also, I cleared up the original graph to represent the estimate muzzle velocities I had listed in the legend that it may have been hard to see:</p><p></p><p></p><p><img src="http://i1237.photobucket.com/albums/ff476/s25075/OGWnumber3.png" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p></p><p>Obviously these are not hard and fast numbers to live by; they only take velocity and bullet weight into consideration and not <u>shot placement</u>, <u>expansion</u>, or how <u>armoured</u> the animal is. If you can take out a 1500lb animal at 1500 yards with a 7 WSM that's great, don't stop because of me. I'm just sharing my own detailed ''mathematical analysis' of the predicted merit of a few great LRH calibres.</p><p>The formula I'm using estimates that at that remaining velocity, your optimal game weight at that range is about 230lbs or lighter, but then again, this is all speculative/comparative math.</p><p></p><p></p><p></p><p>So recently I found the 338 Norma Mag and have been oggeling over that for the past 24 hours. I never saw myself as a 338 guy but this relatively new chambering has got me excited. Punching the numbers into a ballistics calculator yield some interesting trajectories when compared to the 7 WSM 180gn Hybrid:</p><p></p><p></p><p></p><p><img src="http://i1237.photobucket.com/albums/ff476/s25075/338NMvs7mmWSM.png" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p></p><p></p><p></p><p>Basically, the 338 NM will <u>reduce wind drift</u>, <u>increase barrel life</u> (by about 2-3 times), dramatically <u>increase lethality</u>, and, believe it or not, I estimate it should <u>reduce recoil</u> by ~9% assuming the same rifle weight and the addition of a muzzle brake that offers a 30% reduction in felt recoil (je pense un VIAS va suffire<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite11" alt=":rolleyes:" title="Roll Eyes :rolleyes:" loading="lazy" data-shortname=":rolleyes:" />). The only 2 cons to this larger calibre I can think of are <strong>cost,</strong> which I estimate is offset by barrel life (about 60% more $$ or ~5:3 shots per same $$ compared to the 7WSM), as well as <strong>bullet drop</strong>, which is a deterministic variable so who cares? My SWFA SS HD 5-20x50 FFP has a true 30 mils of elevation and my calcs suggest the 338 NM needs 24 mils (83 MoA) at 2000 yards in a standard atmosphere.</p><p></p><p></p><p></p><p></p><p>Anyway, moving on to my new question: I mentioned 'dramatically <u>increased lethality</u>' and am now wondering, <strong>how much is too much? </strong>To get us started, I plotted the following OGW graph, using the rumored 195gn .284 bullets (G7 BC 0.406) to give the 7mm WSM a bit of a leg up:</p><p></p><p><img src="http://i1237.photobucket.com/albums/ff476/s25075/OGW7mmWSMvs338NM.png" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p></p><p></p><p>Again, we see the real benefits of the larger calibre are for the larger animals. The 338 NM offers the following increases in 'maximum' range for the following animals:</p><p></p><p></p><ul> <li data-xf-list-type="ul">200 pound animal: 35% range increase</li> <li data-xf-list-type="ul">450 pound animal: 59% range increase</li> <li data-xf-list-type="ul">1000 pound animal: 184% range increase</li> <li data-xf-list-type="ul">1500 pound animal: ---</li> </ul><p>I know these results are based of the math used to get the numbers but does anyone have any insight into why Edward Matunas chose this type of relationship for his OGW equation? For anyone who's wondering, the equation is as follows:</p><p></p><p></p><p>OGW = V^3 * M^2 * 1.5*(10^-12); where V is <u>remaining velocity</u> in fps and M is <u>bullet weight</u> in grains.</p><p></p><p></p><p></p><p></p><p>Anyway, to wrap this up, I'm thinking if I do go 338 NM, I'd need a short range 'through and through' load with very low expansion for small animals at relatively short ranges. Would you say that even this is overkill for a 200 pound animal?</p><p></p><p></p><p></p><p></p><p>Thanks fo the input gents!</p></blockquote><p></p>
[QUOTE="Haagen Dazs, post: 632778, member: 42602"] [b]338 Norma Mag? How much is too much?[/b] To answer some questions, I'm not going to compare handguns because it's a big no-no up here in Kanukistan. I'm also just looking at long range chamberings and basing everything of a suggested formula that may or may not be accurate for certain bullet/velocity combos. Also, I cleared up the original graph to represent the estimate muzzle velocities I had listed in the legend that it may have been hard to see: [IMG]http://i1237.photobucket.com/albums/ff476/s25075/OGWnumber3.png[/IMG] Obviously these are not hard and fast numbers to live by; they only take velocity and bullet weight into consideration and not [U]shot placement[/U], [U]expansion[/U], or how [U]armoured[/U] the animal is. If you can take out a 1500lb animal at 1500 yards with a 7 WSM that's great, don't stop because of me. I'm just sharing my own detailed ''mathematical analysis' of the predicted merit of a few great LRH calibres. The formula I'm using estimates that at that remaining velocity, your optimal game weight at that range is about 230lbs or lighter, but then again, this is all speculative/comparative math. So recently I found the 338 Norma Mag and have been oggeling over that for the past 24 hours. I never saw myself as a 338 guy but this relatively new chambering has got me excited. Punching the numbers into a ballistics calculator yield some interesting trajectories when compared to the 7 WSM 180gn Hybrid: [IMG]http://i1237.photobucket.com/albums/ff476/s25075/338NMvs7mmWSM.png[/IMG] Basically, the 338 NM will [U]reduce wind drift[/U], [U]increase barrel life[/U] (by about 2-3 times), dramatically [U]increase lethality[/U], and, believe it or not, I estimate it should [U]reduce recoil[/U] by ~9% assuming the same rifle weight and the addition of a muzzle brake that offers a 30% reduction in felt recoil (je pense un VIAS va suffire:rolleyes:). The only 2 cons to this larger calibre I can think of are [B]cost,[/B] which I estimate is offset by barrel life (about 60% more $$ or ~5:3 shots per same $$ compared to the 7WSM), as well as [B]bullet drop[/B], which is a deterministic variable so who cares? My SWFA SS HD 5-20x50 FFP has a true 30 mils of elevation and my calcs suggest the 338 NM needs 24 mils (83 MoA) at 2000 yards in a standard atmosphere. Anyway, moving on to my new question: I mentioned 'dramatically [U]increased lethality[/U]' and am now wondering, [B]how much is too much? [/B]To get us started, I plotted the following OGW graph, using the rumored 195gn .284 bullets (G7 BC 0.406) to give the 7mm WSM a bit of a leg up: [IMG]http://i1237.photobucket.com/albums/ff476/s25075/OGW7mmWSMvs338NM.png[/IMG] Again, we see the real benefits of the larger calibre are for the larger animals. The 338 NM offers the following increases in 'maximum' range for the following animals: [LIST] [*]200 pound animal: 35% range increase [*]450 pound animal: 59% range increase [*]1000 pound animal: 184% range increase [*]1500 pound animal: --- [/LIST] I know these results are based of the math used to get the numbers but does anyone have any insight into why Edward Matunas chose this type of relationship for his OGW equation? For anyone who's wondering, the equation is as follows: OGW = V^3 * M^2 * 1.5*(10^-12); where V is [U]remaining velocity[/U] in fps and M is [U]bullet weight[/U] in grains. Anyway, to wrap this up, I'm thinking if I do go 338 NM, I'd need a short range 'through and through' load with very low expansion for small animals at relatively short ranges. Would you say that even this is overkill for a 200 pound animal? Thanks fo the input gents! [/QUOTE]
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Independent Study: LRH calibres - 7mm WSM vs 300 RUM vs 338 LM
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