muncie21 Posted January 18, 2017 Share Posted January 18, 2017 (edited) I've been shooting USPSA for several years, however only decided to start reloading recently. I'm working to develop a minor load using Bayou 124g TCN and RN bullets, using VV N320 powder. In my most recent tests: I've got the RN loaded with 3.8g and seated at 1.15 OAL, they are chrono'ing at an average of 982 FPS. The TCNs chrno a bit faster than the RNs using the same load. So the TCNs are averaging 985 with 3.7g, when seated at 1.08 (I'm shooting a CZ, so need shorter than typical OAL) With the 124 bullet, both loads (RN & TCN) are below minor PF. VV's website shows max velocity for FP & RN to be 1096 and 1070 respectively. So here's my question, I'd rather not load to max, to get to a 130 PF (I like a little bit of cushion), any suggestions? BTW, I plunk test every round, so I'm confident the bullets are not engaging the rifling. I've also pulled the bullets on some loaded rounds to check for crimp marks on the bullets, very light to no marks on the samples I've pulled. Edited January 18, 2017 by muncie21 Link to comment Share on other sites More sharing options...
Sarge Posted January 18, 2017 Share Posted January 18, 2017 You can do what most others will say and load some at 3.9, 4.0, 4.1 etc and chrono looking for pressure signs etc. 3.8 isn't even close to what you need. 130 PF is not enough cushion for me. I generally aim for 7 over minimum. You won't be able to tell the difference between 130 and 133 anyway. if you want a good 132-133 load without making repeated changes to the press, load them to 4.1 and chrono. Will be mighty close to perfect. Link to comment Share on other sites More sharing options...
IDescribe Posted January 18, 2017 Share Posted January 18, 2017 ^^^ Everything Sarge said ^^^ Viht doesn't have exact data for the bullets you're using, but it has data for two bullets that are relevant. When you're looking for data, match bullet weight first -- 124/125 -- then surface type second -- lead. They list data for two bullets for that: the 124gr Intercast LSWC, with a load window of 3.8gr - 4.1gr -- AND the Ranier 124gr RN, which is supposed to use lead data, so it works both ways, and that is 3.8gr - 4.1gr. It looks like you have some agreement there between your two relevant bullets. I'd say your load window is 3.8 - 4.1gr. I know you're trying to be safe, but at 3.8gr, YOU are loading at the bottom of the load window. You might not even be getting a good pressure seal. It's safe for you to move up, and N320 is very well-behaved. Link to comment Share on other sites More sharing options...
muncie21 Posted January 18, 2017 Author Share Posted January 18, 2017 Thanks (both) for your feedback. ID you're correct in that I'm trying to be safe/conservative with the load. My worry is with the TCN bullet. It needs to be seated ~1.08 in order to pass the plunk test. The load chart on VV's web site list the OAL as 1.142 (except Megashock) and max powder at 4.1. Link to comment Share on other sites More sharing options...
Sarge Posted January 18, 2017 Share Posted January 18, 2017 9 minutes ago, muncie21 said: Thanks (both) for your feedback. ID you're correct in that I'm trying to be safe/conservative with the load. My worry is with the TCN bullet. It needs to be seated ~1.08 in order to pass the plunk test. The load chart on VV's web site list the OAL as 1.142 (except Megashock) and max powder at 4.1. I'm not saying one doesn't need to play it safe when reloading, but when loading 9 minor ammo, unless you just ignore the charts and add a bunch of extra powder you will be fine. Powder companies are VERY conservative with recipes due to liability. A modern 9mm pistol will run +P+ defense ammo with no problem to an extent. When loading 132 PF loads that's more like running weak REM UMC stuff. Then throw in what IDescribe said about differing bullets etc we are are almost always experimenting with these loads and sometimes just safely guessing about oal differences etc. My point being, unless you are just wreckless you are not going to go from 130 PF to +P+ by upping powder .2 or so over the charts or shortening a load by .001. Someday if you ever load 9 MAJOR, THEN you need to be a little OCD since the book loads stop 3.5 grains from where you need to be! Link to comment Share on other sites More sharing options...
IDescribe Posted January 18, 2017 Share Posted January 18, 2017 First, I'm assuming you're talking about the Bayou 124gr TCG. I'm not familiar with a TCN. In developing loads, the OAL difference is good to pay attention to, but you need to recognize that when you are looking at different profiles, it's no longer an apples to apples comparison. There is a point on the ogive that is going to make contact with the rifling with both bullets. Your max OAL is dependent on how far past that point the bullet extends. An RN is more likely to extend further ahead of that point that a truncated cone, in part because the truncated cone is... well... truncated. And the space between the nose and that point on the ogive that will contact the rifling has NO BALLISTIC EFFECT in terms of how the powder burns. What will have an effect on how the powder burns is how deeply the bullet's base is seated into the case. The deeper the base is seated, the smaller the initial size of the combustion chamber is, and the faster and higher pressures will climb. That seating depth is really what you're trying to account for when you adjust for OAL differences, but when the bullets are different profiles, it's not apples to apples. For a specific example, that Bayou 124gr TCG plunks and spins freely at 1.079 in my 75 Shadow Line. I seat it at an OAL of 1.070. The old model BBI 125gr RN, I used to seat at an OAL of 1.1. That's an OAL difference of .04, which might concern someone trying to account for OAL difference, but in reality, the Bayou TCG at 1.07 has a seating depth of .240, and that old BBI 125gr RN at OAL 1.1 had a seating depth of .246, so the bullet with the longer OAL was actually seated deeper, and that's where you're going to affect powder burn and pressure. The truth is that the seating depths are so close together -- .006 -- that the difference isn't even worth worrying about, but the point is that a difference in OAL between two different profiles may not mean much difference at all in terms of seating depth, which is where the real difference in how pressures build comes from. And to make the same point in a different way, I also have used the MBC 125gr SWC, which I have to seat at 1.066, and THAT is a seating depth of .310. So if compared to the 124gr TCG, we have two lead bullets where the OAL difference is only .004, almost the same, but we have a seating depth difference of .070, and THAT is significant and should be accounted for. So it's not just OAL. As I've said many times, the powder doesn't care how much distance there is from the headstamp to the nose; the powder cares how far you jammed the bullet down into its space. And as to not wanting to load near max... why? Max is max standard pressure. Above that is +P. Above that is +P+ and proof loads. I will be the first person to say that people are better off not running up in +P as standard practice while looking for ever softer and softer recoil, but you certainly don't need to be shy of max standard for fear you might drift a hair over. Don't sweat it. Link to comment Share on other sites More sharing options...
muncie21 Posted January 18, 2017 Author Share Posted January 18, 2017 Thanks again Sarge & ID, what you said makes sense. Now I need to load up some more test rounds and get out and test/chrono them. BTW, I was referring to the Bayou TCG bullet, not sure how TCN got lodged in my head. Link to comment Share on other sites More sharing options...
perttime Posted January 18, 2017 Share Posted January 18, 2017 Vihtavuori is playing it safe in their data too. Work up in small steps and pay attention to any flattened primers or other unusual things. VV's max loads of 4.1 gr for 124gr lead bullets seem to be in Minor with a bit of margin - and that is with a 4" test barrel. Your low velocities could mean that you don't have enough pressure. I wonder if your bullets are a fraction too small for your barrel... Link to comment Share on other sites More sharing options...
CZ85Combat Posted January 19, 2017 Share Posted January 19, 2017 I have loaded 20,000 coated 124gn -125gn bullets for my CZ accu-Shodow. 3.9gn N320 @ 1.110" OAL 1050fps 130pf. Have loaded as high as 4.2gn Link to comment Share on other sites More sharing options...
muncie21 Posted January 19, 2017 Author Share Posted January 19, 2017 Looks like I'm headed (slowly) in the right direction. Created a test set at 3.8 and 3.9g and chrono'd them today. It looks like a 4.0g load will put me solidly in the 130PF range Set: 13Created: 01/19/17 11:54Description: 124 TCGNotes 1: 3.8grNotes 2: 1.08 COLDistance to Chrono(FT): 8.00Ballistic Coefficient: 1.000Bullet Weight(gr): 124.00Temp: 40 °FBP: 30.08 inHgAltitude: 0.00# FPS FT-LBS PF10 1028 291.02 127.479 1049 303.03 130.088 1028 291.02 127.477 1018 285.39 126.236 1032 293.29 127.975 1044 300.15 129.464 1017 284.83 126.113 1016 284.27 125.982 1029 291.59 127.601 1000 275.38 124.00Average: 1026.1 FPSSD: 14.2 FPSMin: 1000 FPSMax: 1049 FPSSpread: 49 FPS Set: 15Created: 01/19/17 11:59Description: 124 TCGNotes 1: 3.9gNotes 2: 1.08 COLDistance to Chrono(FT): 8.00Ballistic Coefficient: 1.000Bullet Weight(gr): 124.00Temp: 40 °FBP: 30.10 inHgAltitude: 0.00# FPS FT-LBS PF10 1037 296.14 128.599 993 271.54 123.138 1019 285.95 126.367 1053 305.35 130.576 1040 297.85 128.965 993 271.54 123.134 1050 303.61 130.203 1035 295.00 128.342 1048 302.45 129.951 1017 284.83 126.11Average: 1028.5 FPSSD: 22.2 FPSMin: 993 FPSMax: 1053 FPSSpread: 60 FPS Link to comment Share on other sites More sharing options...
Sarge Posted January 19, 2017 Share Posted January 19, 2017 I would still shoot for 132. Link to comment Share on other sites More sharing options...
IDescribe Posted January 20, 2017 Share Posted January 20, 2017 I agree with Sarge, Muncie. I'd up your velocity a bit more, as well. If you're worried about recoil, think of it this way: your extreme spreads of 50 and 60 with a 124gr bullet equals a PF spread of 6 and 7 respectively. Did you notice the different recoil from one round to the next when shooting those? No? So don't sweat moving up a couple more PF from a recoil standpoint. You'll never notice. Link to comment Share on other sites More sharing options...
muncie21 Posted January 20, 2017 Author Share Posted January 20, 2017 (edited) Yep, as always you're both on point (Sarge/ID) I'm going to target a 132/133 PF. Loaded up another set and can't wait to try'em out! I'm also a bit curious to see if there is a noticeable difference in velocity between the TCG and RN bullets at this load. I'm really digging the intricacies and complexity that comes with reloading, but then again, I've always enjoyed a good puzzle. Edited January 20, 2017 by muncie21 Link to comment Share on other sites More sharing options...
BillGarlandJr Posted January 20, 2017 Share Posted January 20, 2017 On 2017-01-18 at 7:28 AM, Sarge said: You can do what most others will say and load some at 3.9, 4.0, 4.1 etc and chrono looking for pressure signs etc. 3.8 isn't even close to what you need. 130 PF is not enough cushion for me. I generally aim for 7 over minimum. You won't be able to tell the difference between 130 and 133 anyway. if you want a good 132-133 load without making repeated changes to the press, load them to 4.1 and chrono. Will be mighty close to perfect. I've shot a lot of the above load. Makes pf without fail, is accurate, and runs the gun well (P320, G34, and XDM 5.25) in my experience. A good recommendation. Link to comment Share on other sites More sharing options...
bandw1dth Posted January 20, 2017 Share Posted January 20, 2017 Yep, as always you're both on point (Sarge/ID) I'm going to target a 132/133 PF. Loaded up another set and can't wait to try'em out! I'm also a bit curious to see if there is a noticeable difference in velocity between the TCG and RN bullets at this load. I'm really digging the intricacies and complexity that comes with reloading, but then again, I've always enjoyed a good puzzle.I too enjoy the complexity and intricacies of reloading. Just when I think I've finally got a firm grasp on it I find something that makes me realize just how much I don't know. Link to comment Share on other sites More sharing options...
muncie21 Posted January 20, 2017 Author Share Posted January 20, 2017 Here's the data from the latest test set using 4.0g of N320 and a target OAL of 1.08. I'm pretty happy with these, now to crank out some and start practicing. Created: 01/20/17 11:48Description: 124 TCGNotes 1: 4.0gNotes 2: 1.08 OALDistance to Chrono(FT): 6.00Bullet Weight(gr): 124.00Temp: 49 °FBP: 29.76 inHg# FPS FT-LBS PF10 1048 302.45 129.959 1075 318.24 133.308 1076 318.83 133.427 1086 324.79 134.666 1086 324.79 134.665 1080 321.21 133.924 1103 335.03 136.773 1057 307.67 131.072 1085 324.19 134.541 1089 326.58 135.04Average: 1078.5 FPSSD: 15.9 FPSMin: 1048 FPSMax: 1103 FPSSpread: 55 FPSShot/sec: 0.6True MV: 1079 FPS Link to comment Share on other sites More sharing options...
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