thefish Posted November 23, 2007 Share Posted November 23, 2007 If all else is equal, (including velocity, bullet weight, OAL, etc.) does a JHP allow more accuracy than a CMJ because for a given weight, the JHP has more bearing surface to contact the barrel and thus more stability? Link to comment Share on other sites More sharing options...
smokshwn Posted November 23, 2007 Share Posted November 23, 2007 No, the edge in accuracy comes from the JHP having more of its weight towards the base of the bullet. Link to comment Share on other sites More sharing options...
Front Man Posted November 23, 2007 Share Posted November 23, 2007 The same reason Porsche puts their engines in the rear. To fly better. FM Link to comment Share on other sites More sharing options...
thefish Posted November 23, 2007 Author Share Posted November 23, 2007 If you had to quantify it...about how much of an increase in accuracy do you see, say at 25yds in reasonably "skilled" hands? Link to comment Share on other sites More sharing options...
smokshwn Posted November 23, 2007 Share Posted November 23, 2007 If you are talking like quality bullets (MG JHP vs. MG CMJ or Zero JHP vs. Zero CMJ) the difference is most likely not noticeable.... Link to comment Share on other sites More sharing options...
thefish Posted November 24, 2007 Author Share Posted November 24, 2007 If you are talking like quality bullets (MG JHP vs. MG CMJ or Zero JHP vs. Zero CMJ) the difference is most likely not noticeable.... At what distance do you think it does become noticeable...a distance that would realistically be used by handgunners in any competition? This applies across all handguns shooting under the same conditions? Thanks Link to comment Share on other sites More sharing options...
smokshwn Posted November 24, 2007 Share Posted November 24, 2007 My experience with handguns outside of IPSC/USPSA is pretty limited so you are getting a little out of my realm of experience. My guess is that a bullseye type shooter may notice a difference but I certainly can't. Link to comment Share on other sites More sharing options...
G-ManBart Posted November 24, 2007 Share Posted November 24, 2007 No, the edge in accuracy comes from the JHP having more of its weight towards the base of the bullet. I think that there's definitely something to that, but I'm not sure it's the only factor. I've been shooting the MG 121gr IFP lately and it's a very, very accurate bullet. It's their 115gr JHP with the cavity filled in, so they've moved the center of gravity forwards a bit. Years ago I was talking with a high level benchrest shooter about bullets and he said they all used HP designs because they were more accurate, but it wasn't only because of the placement of the weight and the empty cavity that factored into it. The other factor was based upon how the bullets are made....with a HP, the method of making them is different. They dray/extrude the copper partially, pour the lead in and then finish extruding the copper over the lead, leaving the hollow area filled with a punch that is used to push the bullet out of the forming die/mold (not sure of what it's called). He said this method lead to a more consistent jacket and more consistent lead on the inside (or something along those lines). Later, I read an article about how Sierra manufactured the .308 168gr match HP bullets. Turns out the hollow point is a byproduct of the manufacturing process rather than a design element to increase accuracy. Interesting stuff, but it's way over my head! Link to comment Share on other sites More sharing options...
DougCarden Posted November 24, 2007 Share Posted November 24, 2007 My experience with steel loads......Remington 88 jhps and their 95gr JRN bullets. Same OAL, same powder, same everything. In my guns at 40yds the 88s will shoot on top of each other everytime. One holer if I do my part. When I started loading up the 95s, thinking they would be a great cheaper alternative.....I got circular groups of 2-3 inches, with flyers well outside that inner group. It sure woke me up and made me understand that there is no cheap way to get good accuracy. I have experienced 115fmj to open up groups about 2in or so at 25yds versus 115 jhps as well. I am having a 6in 9x19 built for Bianchi type events, and will test my "accurate" 115fmj loads versus the 115jhp loads as well, but I know that the jhps will shoot much better. Hope that helps.... Good luck, DougC Link to comment Share on other sites More sharing options...
AlamoShooter Posted November 24, 2007 Share Posted November 24, 2007 Printed material will tell you that the back side = last out the barrel will have the most to do with accuracy not the front. Like in a rifle bullet and a canoe the air filling in behind the bullet when it leaves the barrel has to do with its rotation being consistent. I think the "Old" thing with HP bullets was that the bullet normally was of better quality as compared to cheaper Ball ammo. Look for a nice sharp consistent back edge MG are nice the Zeros are nice. I don't shoot off a ransome rest . or even locking the gun in the sand bags. What I do is put the sand bags under my wrists and test like the gun is in normal recoil. 2" at 35 -40 yards is what I call a great group for a load in a race gun. For STC I want a load and gun that will do better But STC and IPSC are not really close. But thin I don't know much Link to comment Share on other sites More sharing options...
Jaxshooter Posted November 24, 2007 Share Posted November 24, 2007 I have shot MG 115 JHPs, MG 121 IFPs and Zero 125 JHPs in my 9mm open gun. The MG 121 IFP is far more accurate than the other two in my gun. Link to comment Share on other sites More sharing options...
thefish Posted November 24, 2007 Author Share Posted November 24, 2007 I have shot MG 115 JHPs, MG 121 IFPs and Zero 125 JHPs in my 9mm open gun. The MG 121 IFP is far more accurate than the other two in my gun. I have shot Montana Gold before and like them as well. What is this IFP you mentioned? On their (MG's) site, they have it, but only in 9mm..."International Full Pro"...what is it? Why not in other cals? Thanks Link to comment Share on other sites More sharing options...
thefish Posted November 24, 2007 Author Share Posted November 24, 2007 (edited) A poll for all...is there a general consensus that all other variables controlled, that a JHP vs. CMJ might make a difference but not a substantial one in a pistol cartridge (9mm, .40 or .45) at under 25yds? Edited November 24, 2007 by thefish Link to comment Share on other sites More sharing options...
Kingman Posted November 24, 2007 Share Posted November 24, 2007 the guys that shoot bianchi would be the best to ask, many of them shoot jhp's and say they group better. For bullseye I shoot wadcutters that have almost all the weight at the back. my .45 will group under 2 at 50 for 5 shots. Link to comment Share on other sites More sharing options...
Scott R Posted November 24, 2007 Share Posted November 24, 2007 I have shot MG 115 JHPs, MG 121 IFPs and Zero 125 JHPs in my 9mm open gun. The MG 121 IFP is far more accurate than the other two in my gun. I have shot Montana Gold before and like them as well. What is this IFP you mentioned? On their (MG's) site, they have it, but only in 9mm..."International Full Pro"...what is it? Why not in other cals? Thanks They designed them for IPSC Open division rules (not USPSA) APPENDIX D1 Open Division 3 Minimum bullet weight 120 grain for Major US APPENDIX D6 US Open Division 3 Minimum bullet weight 112 grain for Major Looks like they just filled in the hollow point of a 115jhp to meet the bullet wieght criteria for IPSC Open. Link to comment Share on other sites More sharing options...
G-ManBart Posted November 25, 2007 Share Posted November 25, 2007 I have shot MG 115 JHPs, MG 121 IFPs and Zero 125 JHPs in my 9mm open gun. The MG 121 IFP is far more accurate than the other two in my gun. I have shot Montana Gold before and like them as well. What is this IFP you mentioned? On their (MG's) site, they have it, but only in 9mm..."International Full Pro"...what is it? Why not in other cals? Thanks As Scott mentioned, the 121gr IFP is definitely the 115gr JHP with the cavity filled in. There isn't as much a need for it in the U.S. but it seems a number of us are using them. They're a touch flatter shooting than the 125s in my gun and seem a bit softer than the 115s, but I haven't used many 115s yet....cause I have something like 13K of 121 and 125s to use up first! They measure a bit over .355 and shoot equally well out of most 9mm and 38 Super/Supercomps from all the reading I've done on them. On your other question, it's probably unusual to find a gun that won't shoot a good CMJ/FMJ well enough for IPSC shooting. I load my match ammo for my limited gun with 180gr JHP Zeros and load 180gr CMJ or FMJs for practice (whichever I can get cheaper in bulk). There have been plenty of times when I didn't have enough match ammo loaded and I used my practice stuff at local matches....it's more than good enough really. I get 25yd groups around 1.25" with the Zero JHPs and the other bullets might open that up to 2 or 2.5" at worst...not enough to be a factor in our matches. If you were going to shoot a match with lots of 40 and 50yd shots it would be worth considering, but that's not too common. R, Link to comment Share on other sites More sharing options...
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