dpete Posted April 7, 2015 Report Share Posted April 7, 2015 I just got back from my latest range trip and I'm smiling. Its nice when a plan comes together. The first target group is the charge weight ladder which I shot last week. Nothing amazing jumped out at me during my round robin shooting, but the 48.7gr & 49.0gr charges had roughly the same POI centers so I went with 48.8 as my charge weight. Hodgdon lists 49.0gr as top for CFE223 in a .308 and I wanted at least a little room below that. The second set of targets is what I shot today. All of the charges were 48.8gr of CFE223 and I stepped up by .005" for each group starting at 2.790". Thanks to reading past posts here and taking the advice I received in my earlier post about cartridge length I pulled everything I had loaded below 2.790. I stepped up to 2.815" instead, which is as long as I could go and still have clearance inside the Pmags I have. The lower left target is the 5 sighting shots I took before starting the round robin with the 6 lengths. The 2.800" group is similarly shaped to the previous one I shot last week and I found it amazing how much the groups closed up as the bullets lengthened. I think 2.815" is going to be a winner with this load. Hornady 168gr HPBT Match #30501 Rem. .308 cases CCI 200 primers 48.8 gr CFE223 Quote Link to comment Share on other sites More sharing options...
Toolndie7 Posted April 7, 2015 Report Share Posted April 7, 2015 Wow, really shrunk that group up nice. Looks like you got it dialed in. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted April 7, 2015 Report Share Posted April 7, 2015 I would go with the 2.795 , myself . Quote Link to comment Share on other sites More sharing options...
dpete Posted April 8, 2015 Author Report Share Posted April 8, 2015 I would go with the 2.795 , myself . What are you seeeing there that I'm missing? It was some of your past posts that got me thinking about trying various lengths. Quote Link to comment Share on other sites More sharing options...
Magwa Posted April 8, 2015 Report Share Posted April 8, 2015 2.815 is the winner by far no need to test any further load and shoot..... Quote Link to comment Share on other sites More sharing options...
AngelDeVille Posted April 8, 2015 Report Share Posted April 8, 2015 Nice progression! Your next task is to build two more rifles and optimize the load and oal for all three rifles. Start......... NOW! :banana: :banana: :banana: Quote Link to comment Share on other sites More sharing options...
dpete Posted April 8, 2015 Author Report Share Posted April 8, 2015 Nice progression! Your next task is to build two more rifles and optimize the load and oal for all three rifles. Start......... NOW! :banana: :banana: :banana: LOL, I already have 3 other ARs that I load for. A 5.56 Colt M4 and two 300 Blackouts, one a 16" carbine, the other an 8" pistol. The 2 blackouts may not count though because they both shoot the same bullets equally well. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted April 8, 2015 Report Share Posted April 8, 2015 What are you seeeing there that I'm missing? It was some of your past posts that got me thinking about trying various lengths. Its good to try different COL's , all Chambers are different , whats good for one may not be the right or best for another . The 2.795 are , to me , a more consistent grouping . The 2.800 & 2.815 " also show the same consistency , but I would rather have a Cartridge that I know will function in any mag. in my collection , than a very small difference in grouping . It only takes one Cartridge in that mag to move under recoil to have a stoppage , when the COL takes up the available space in the mag. seen it happen . Good shooting . Quote Link to comment Share on other sites More sharing options...
dpete Posted April 8, 2015 Author Report Share Posted April 8, 2015 It only takes one Cartridge in that mag to move under recoil to have a stoppage , when the COL takes up the available space in the mag. seen it happen . Good shooting . I had wondered about being that close to the inside of the mag. I'll have to do some measuring again on the Pmags and ASCs that I have and do some considering. The stoppage part of it I hadn't thought of. Thanks Quote Link to comment Share on other sites More sharing options...
hollywood Posted April 9, 2015 Report Share Posted April 9, 2015 Dpete, Have you checked max oal in the chamber to see how much jump you have? I load to similar OAl in my RRA Lar-8. I'm jumping .105. Quote Link to comment Share on other sites More sharing options...
MikedaddyH Posted April 9, 2015 Report Share Posted April 9, 2015 Its good to try different COL's , all Chambers are different , whats good for one may not be the right or best for another . The 2.795 are , to me , a more consistent grouping . The 2.800 & 2.815 " also show the same consistency , but I would rather have a Cartridge that I know will function in any mag. in my collection , than a very small difference in grouping . It only takes one Cartridge in that mag to move under recoil to have a stoppage , when the COL takes up the available space in the mag. seen it happen . Good shooting .This happened to me at our shoot at Jon's Range, with Vera. .223 loads measured to mag length for steel mags got stuck in the ThermoMelts. Remember that Tom ! Quote Link to comment Share on other sites More sharing options...
dpete Posted April 9, 2015 Author Report Share Posted April 9, 2015 Dpete, Have you checked max oal in the chamber to see how much jump you have? I load to similar OAl in my RRA Lar-8. I'm jumping .105. No I haven't. I don't have an oal gauge, but its something I should do. Quote Link to comment Share on other sites More sharing options...
hollywood Posted April 9, 2015 Report Share Posted April 9, 2015 I've only recently checked to see what it was because I was going to do similar testing with 175gr smk and was curious. My 168gr smk shoot quite well with that amount of jump and have even done ery well with hornady 110gr vmax with that jump. So having seating very close may not be as critical as I thought previously. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 16, 2015 Report Share Posted April 16, 2015 I'd like to hear from N Jensen on seating just off the lands - or how far to seat off the lands. That's gonna be the one guy here that has the most experience on that... <thumbsup> Quote Link to comment Share on other sites More sharing options...
Magwa Posted April 16, 2015 Report Share Posted April 16, 2015 as stated before each barrel -chamber is different I have loaded for different calibetrs anywhere from 40 to 120 off the lands barnes bullets like a long jump back 20 some years ago when I started loading barnes it took a while to find this out they were a bitch to get a group with, now they are a much better bullet and much easier to load for each round , powder charge can effect jump but you will find the sweet spot for each rifle by experimenting. take a black magic marker and cover the area around the ogive then gently chamber the round a( dummy round) I should have said with the bullet seated very shallow so that when chambering it slides the bullet into the case when you take that round out there will be marks in the magic marker now you have the depth of your chamber and you can start adding jump to the bullet by seating it deeper ...it is a long process but it is worth it now in AR platforms you will be held to mag dimensions but with gun like a ruger number one (my preferred sniper rifle) your limits go away... Quote Link to comment Share on other sites More sharing options...
Cali_Ed Posted April 20, 2015 Report Share Posted April 20, 2015 Hmmm makes me wonder if testing dif c.o.a.l is worth it... Quote Link to comment Share on other sites More sharing options...
MikedaddyH Posted April 20, 2015 Report Share Posted April 20, 2015 Hmmm makes me wonder if testing dif c.o.a.l is worth it...I would say.. yes... I found two sweet spot's with the 168gr bthp bullets. At2.795" and 2.806" ,both accuracy and velocity of promo. Also it fits all of my mags. Quote Link to comment Share on other sites More sharing options...
Cali_Ed Posted April 24, 2015 Report Share Posted April 24, 2015 I run everything at 2.8, seems like it would be a bad idea lowering that on a compressed load? Quote Link to comment Share on other sites More sharing options...
dpete Posted April 25, 2015 Author Report Share Posted April 25, 2015 I run everything at 2.8, seems like it would be a bad idea lowering that on a compressed load? Once again it depends on the powder charge. If your rifle performs well on lighter charges you have more wiggle room to shorten the COAL and not run into pressure signs. That was my reasoning with trying to lengthen my bullets OAL. Seating farther out proportionally lowers the pressure as long as you aren't jamming the bullet into the lands. For comparison, the bullets in the opening post used Remington cases, 48.8 grains of CFE223, and the rifle liked the 2.815 length. I found that using Hornady 308 Match cases the rifle liked the 2.815 length even more (100 yard group covered by a quarter). Since then I've acquired about 2 gallons worth of LC brass and in that brass using the same Hornady 168 grain BTHP Match bullets the rifle is liking 47.5 grains as opposed to the 48.8 in my OP. I'm still tweaking the LC charge weight and then will tweak the OAL to see what happens then. Quote Link to comment Share on other sites More sharing options...
AngelDeVille Posted April 25, 2015 Report Share Posted April 25, 2015 Generally powders that require compressed charges aren't the highest velocity, and pressure. Quote Link to comment Share on other sites More sharing options...
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