MilkMyDuds Posted January 25, 2015 Share Posted January 25, 2015 I am reloading using SDB, and noticed recently that with different head stamps I am getting different group sizes. I have 2 identical guns, both MP9 Pro 5'' with KKM barrel, for the testing. It's not any fancy test but rather just shooting from a rest at 25 yards. For example, FC gives me best group size around 2 inches, from both guns consistently. PMC produced mixed results, some times 2 inches, while other times 5 inches. I have done hundreds of rounds of testing. The trend is pretty obvious that FC head stamp seems to perform the best. Given that I run all mixed head stamp through my SDB with the same die settings, is it possible that the wall thickness + neck tension + OAL of the FC brass just resulted in the best rounds for my guns? I guess this can be due to crimping. The bullet I used are Berry's 147gr or Xtreme 147gr plated. I pulled a few of different head stamps and checked the crimp line. In all cases there is only a very vague line, definitely not overcrimped. Any thoughts? Link to comment Share on other sites More sharing options...
Canine582 Posted January 25, 2015 Share Posted January 25, 2015 all my brass is once fired: Win. FC Speer all I know using XTreme's 147 plated at 15 yds, I get groupings about 1 1/2" in size off my bag. That's today with my Beretta 92A1. Link to comment Share on other sites More sharing options...
Kaskillo Posted January 25, 2015 Share Posted January 25, 2015 It is possible that your gun likes a specific HS. Test 10 rounds per HS and see what gives you the best results. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted January 25, 2015 Share Posted January 25, 2015 I wonder if your best groups come from the Xtreme bullets and your worst groups come from the Berrys? Link to comment Share on other sites More sharing options...
MilkMyDuds Posted January 25, 2015 Author Share Posted January 25, 2015 Berry's and Xtremes give me same group size at 25 yards. I have tested 10 shot groups across FC, RP, PMC etc. The best is always from FC and RP. PMC gives me the worst group size in average, but some PMC 10 shot groups do produce group size close to that of FC and RP. BTW - I do not change any die setting/powder amount etc. with Berry's and Xtreme or different head stamps. It may be the KKM barrel that likes FC brass for some reason. I tested on stock MP9 Pro 5 inch barrels and all head stamps produce about the same group size. Link to comment Share on other sites More sharing options...
Sarge Posted January 25, 2015 Share Posted January 25, 2015 Nah, it's the mixed headstamps giving different oals. When I did testing I found my gun was most sensitive to slightly different oals as far as group sizes and actually POI. Link to comment Share on other sites More sharing options...
bugsy Posted January 25, 2015 Share Posted January 25, 2015 I also noticed difference in the diameter of the casing. After re-sizing, I notice Speer being the most consistent, WIN the least consistent, FC, RP average. Grouping from Speer seems to be the tightest. I believe this also depends on the barrel. This result was based on CZ 75 SP01 Shadowline and CZ 85 Combat. Link to comment Share on other sites More sharing options...
amada8 Posted January 25, 2015 Share Posted January 25, 2015 Sarge, this may have been discussed many times in the past in other threads (can't search this exact question though),,,, but why would OAL be different if the only component changed is the case? Doesn't the seating die "set" the OAL? I can see the theory behind the seating depth being different if the height of the case varies. But I don't understand a theory behind different OAL simply because the case is marginally different in case thickness, height or hardness. Thanks in advance for your reply. Link to comment Share on other sites More sharing options...
RDA Posted January 25, 2015 Share Posted January 25, 2015 Sarge, this may have been discussed many times in the past in other threads (can't search this exact question though),,,, but why would OAL be different if the only component changed is the case? Doesn't the seating die "set" the OAL? I can see the theory behind the seating depth being different if the height of the case varies. But I don't understand a theory behind different OAL simply because the case is marginally different in case thickness, height or hardness. Thanks in advance for your reply. Tighter cases will result in longer OAL (seating the bullet has more resistance) and looser cases will result in shorter OAL. Link to comment Share on other sites More sharing options...
Sarge Posted January 26, 2015 Share Posted January 26, 2015 Sarge, this may have been discussed many times in the past in other threads (can't search this exact question though),,,, but why would OAL be different if the only component changed is the case? Doesn't the seating die "set" the OAL? I can see the theory behind the seating depth being different if the height of the case varies. But I don't understand a theory behind different OAL simply because the case is marginally different in case thickness, height or hardness. Thanks in advance for your reply. Tighter cases will result in longer OAL (seating the bullet has more resistance) and looser cases will result in shorter OAL. That is probably the most likely cause. In all the times this has been brought up all I know is (1) oal will vary by headstamp (2) no real clear reason why, they just do. Link to comment Share on other sites More sharing options...
Youngeyes Posted January 26, 2015 Share Posted January 26, 2015 The one thing I know for sure that changes with the head-stamp is the crimp. The longer case goes further into the crimp die. The longer case will get crimped more. This may cause accuracy issues. Link to comment Share on other sites More sharing options...
jayjay1 Posted January 26, 2015 Share Posted January 26, 2015 The 9mm Luger has a very small powder room, if your having a short throat (like CZs do f.e.) it´s even worse. Every brand has it´s own measurements, some have thicker walls or bottoms and so on. Me, liking the soft recoil of heavier bullets with faster powders (Attention with this!), I didn´t want to take to much risk with pressure variations. Because the .40s are very rare over here, I have to use whatever I can get my hands on in this caliber, accepting that this will lead to a suboptimal precision. But to be on the safe side, I´ve measured 5 of all headstamps I had (were about 12 or so). I´ve weighted them all empty, then filled ´em up with soap water and weighted them again. I had differences, from the lightest to the heaviest, from roundabout 15% weight / water volume, what seemed very much to me. So I´ve sorted out all of the two heaviest brands and didn´t look back. But with the 9mm having a even smaller powder room I don´t do that. There I´m using only one brand and that´s it. Link to comment Share on other sites More sharing options...
Youngeyes Posted January 26, 2015 Share Posted January 26, 2015 Good point and nice work jayjay1. I forgot about case volume. The manual always warns that military 30-06 cases have less volume. You need to load 1-2 gr less than commercial. I can imagine what a difference case volume variations can make in a high pressure round like a .40. Do you remember which head stamps had the least/most volume? Link to comment Share on other sites More sharing options...
jayjay1 Posted January 26, 2015 Share Posted January 26, 2015 (edited) Do you remember which head stamps had the least/most volume? Yes sir! I´ve made a list, because I didn´t want to do this twice... Beginning with the one with the least volume, ending with the most volume: Blazer (least powder room) Hornady Winchester (silver ones) Remington Speer FC12 (?) HPR (?) (average volume) S&B WIN (brass) PMC G.F.L. PPU Fiocchi USA When I was ready with weighing them, I thought a little bit about it afterwards and came to the conclusion, that if the outer measurements of the same caliber brass is the same, you don´t need no soap water. Just weigh the empty brass, and the heaviest of them will have the least powder room and vice versa. The more you weigh, the more precise will be your results. In my case, I removed the Blazer cases out of my collection and still do so, if I get some. P.S.: I saw, that it has been almost 10% weight difference between the Blazer and the Fiocchi USA, not 15% like I wrote before. Edited January 26, 2015 by jayjay1 Link to comment Share on other sites More sharing options...
Sarge Posted January 26, 2015 Share Posted January 26, 2015 Do you remember which head stamps had the least/most volume? In my case, I removed the Blazer cases out of my collection and still do so, if I get some. That's a shame because Blazer brass is good stuff! Link to comment Share on other sites More sharing options...
jayjay1 Posted January 26, 2015 Share Posted January 26, 2015 (edited) Do you remember which head stamps had the least/most volume? In my case, I removed the Blazer cases out of my collection and still do so, if I get some. That's a shame because Blazer brass is good stuff! Of course you are right! They use a lot of material, what shows the quality. If I could have Blazer only, I would go further on and won´t look back. But over here, a .40 brass on the ground is like gold. In fact I buy the most of them from a shooting range in the USA. Edited January 26, 2015 by jayjay1 Link to comment Share on other sites More sharing options...
RDA Posted January 26, 2015 Share Posted January 26, 2015 But over here, a .40 brass on the ground is like gold. In fact I buy the most of them from a shooting range in the USA. Hmm, I thought that you couldn't export brass without ITAR approval, I'd be surprised that a shooting range in the US went through that trouble. Link to comment Share on other sites More sharing options...
jayjay1 Posted January 27, 2015 Share Posted January 27, 2015 (edited) Oh, ok, didn´t know that used fired brass falls under ITAR. Humm, worked not only once, so.... Are you sure? If so, I don´t understand ITAR somehow. I can buy new US-American brass for a looooooooooot of money over here legally. As I can buy US-made rifles and pistols and ammos and all the other stuff in any gun shop over here. What is the sence of banning used brass then? Edited January 27, 2015 by jayjay1 Link to comment Share on other sites More sharing options...
truborshooter Posted January 27, 2015 Share Posted January 27, 2015 Laws written by politicians to control the masses....and protect themselves What's there to understand? First brass, then bullets, primers, powder, then guns....... In a less free country they would just break in you door and take what they want. In a modern free country, they vote it in slowly and eventually take what they want Ain't freedom grand? Link to comment Share on other sites More sharing options...
RDA Posted January 28, 2015 Share Posted January 28, 2015 Oh, ok, didn´t know that used fired brass falls under ITAR. Humm, worked not only once, so.... Are you sure? If so, I don´t understand ITAR somehow. I can buy new US-American brass for a looooooooooot of money over here legally. As I can buy US-made rifles and pistols and ammos and all the other stuff in any gun shop over here. What is the sence of banning used brass then? It can be exported, but you have to comply with additional regulations and fees, which are prohibitive for most so they don't bother and simply won't ship internationally (unless they don't know better and do it without complying in which case I believe it is a felony if caught). As far as why, it is my general understanding that they want to inhibit arms, ammunition, and components that can be turned into arms or ammunition from falling into the wrong hands. Link to comment Share on other sites More sharing options...
jayjay1 Posted January 28, 2015 Share Posted January 28, 2015 I understand the idea and totally agree with it, no problem. I don´t ask about the sence of ITAR, but why can I buy any US gun product (including brass) new from any gun dealer over here, but not used brass from a dealer in the US? That´s a little bit absurd to me, not the existence of ITAR itself. Or, is it all about the money? Link to comment Share on other sites More sharing options...
RDA Posted January 29, 2015 Share Posted January 29, 2015 I understand the idea and totally agree with it, no problem. I don´t ask about the sence of ITAR, but why can I buy any US gun product (including brass) new from any gun dealer over here, but not used brass from a dealer in the US? That´s a little bit absurd to me, not the existence of ITAR itself. Or, is it all about the money? It isn't about new or used, it is about regulation. As long as they abide by ITAR, they can sell it. The products you are purchasing purportedly met the ITAR requirements as they were exported from the US. Link to comment Share on other sites More sharing options...
Brooke Posted January 29, 2015 Share Posted January 29, 2015 Nah, it's the mixed headstamps giving different oals. When I did testing I found my gun was most sensitive to slightly different oals as far as group sizes and actually POI. My opinion also! Link to comment Share on other sites More sharing options...
Steve RA Posted January 29, 2015 Share Posted January 29, 2015 You could use mixed for practice and then use the one that groups the best for matches. Just be sure your POA/POI is the same with the best grouping brass. Link to comment Share on other sites More sharing options...
duy Posted February 4, 2015 Share Posted February 4, 2015 im using FC brass for my major matches for the consistency and mixed brass for everything eles. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now