Powder for Bullseye load 9 mm 115 gr ... SIG P210 target ... want to develop an accuracy load for bullseye.
I am not a bullseye match shooter but shot USPSA and my reloading/match shooting mentor was a bullseye/PPC match shooter who was OCD about consistency. What I learned from my mentor and things related to reloading consistency I learned over the decades from seasoned match shooters/THR about producing accurate 9mm loads, especially with 115 gr FMJ/RN bullets that have shorter bullet base that tends to reduce neck tension, consider the following for your load development -
https://www.thehighroad.org/index.p...-and-discussions.778197/page-10#post-11419509
- Reloading variables - 9mm is higher pressure cartridge more susceptible to small internal volume case variance (headstamp), case wall thickness/neck tension/bullet setback, powder charge metering variance, OAL/bullet seating depth, consistency of bullet ogive where seating stem contacts the bullet, bullet diameter (.354"-.356"+), etc.
- Brass selection by case wall thickness - Using thicker case wall brass (.200" below case mouth) where friction with bullet base is greater for 115 gr FMJ/RN bullet, will improve neck tension and eliminate/reduce bullet setback for more consistent chamber pressure build/average peak chamber pressures, especially at lighter target/bullseye match load powder charge range - https://www.thehighroad.org/index.p...neck-tension-and-bullet-setback.830072/page-4
- Sorting brass by resized length - I am assuming you will not be using new brass so greater care needs to be exercised to not only sort mixed range brass for same headstamp but also sort for resized case length as shorter cases will allow shallower bullet seating depth/less neck tension. I would use the longest resized case lengths for my match loads.
- Using shorter OAL - And consider testing shorter OALs to improve neck tension and powder case fill to reduce air gap between flash hole and powder granules as semi-autos usually fire with powder charge forward when the round is chambered and granules slammed forward. For most faster burning than Unique/Universal powders at start to mid range load data using 115 gr FMJ/RN, I have found shorter 1.110"-1.130" OAL to produce smaller groups than longer 1.150"-1.160". But because 9mm is a tapered case with wider base, using shorter than 1.100" OAL started to reduce neck tension to the point where I could push the bullet inside the case.
- Accurate weighing of powder charges - Faster burning than W231/HP-38 often have tighter published start/max charges around 0.5 gr so consistent metering/weighing of powder charges is crucial and I suggest weighing of powder charges with scale verified by a good set of check weights. I use Ohaus ASTM Class 6 stainless steel check weight set that goes down to 1 mg (0.015 gr) - https://www.zoro.com/ohaus-weight-kit-cylndr-500mg-to-1mg-ss-class6-80850110/i/G0843236/
- Bullet weight/ogive consistency - My mentor sorted bullets to .1 gr and would even shave the lead base of FMJ to make them weigh the same. I have found lead/coated lead/plated bullets to vary in weight by 1.0+ gr and jacketed bullets were more consistent in weight variance around 1.0 gr with more consistent bullet nose/ogive where the seating stemp contacts the bullet to produce more consistent OAL. While I used Montana Gold exclusively for my USPSA match loads, in recent years, I have found RMR in-house jacketed bullets to be more consistent in weight (around/less than .05 gr) and OAL to produce .001" variance even with mixed range brass. (If you are using progressive press, I highly recommend separately pre-resizing the brass and hand priming the resized brass) And if you have not made your match bullet selection yet, consider that ELEY recently selected RMR bullets for their new line of match ammunition (Less than .05 gr weight variance and .001" OAL consistency) and produced 1" groups at 25 yards with 5" 1911/Ransom Rest - https://www.thehighroad.org/index.p...-match-ammunition.854750/page-3#post-11282439
- FMJ vs JHP - I started out using FMJ for USPSA match loads (45ACP/9mm then later 40S&W) but switched to JHP at the recommendations from seasoned shooters who claimed JHP bullet with more weight shifted to the bullet base produced longer bullet base (bearing surface that engaged the rifling) for greater rotational stability in flight for smaller groups. Since I shot "action pistol" USPSA matches that did not require bullseye match level of accuracy (I just needed to place all my shots inside the A zone), I never really got to test this out fully (I feel another myth busting thread forming
) but many USPSA and bullseye match shooters prefer JHP so take that into consideration. BTW, RMR produces JHP in 115 gr - https://www.rmrbullets.com/shop/bul...ollow-point-mini-multi-purpose-round-bullets/
Since RMR is back ordered, I can "Pay It Forward" an assortment of RMR 115 gr FMJ, FP (Mini MW), JHP for your testing to see which bullet works best with your pistol. PM me if interested.
OK, that should now help you develop an accurate bullseye match load. Now for powder selection.
My gun prefers 115 gr factory ammo ... Powders I have are Unique, Bullseye, W231, VV 320, VV 310, 700X, Power Pistol, Tight Group and WST.
- Using faster burn rate powders for lighter target loads - For lighter target loads, I found faster burning than W231/HP-38 powders tend to maintain accuracy at lower powder charges likely from faster burn rate producing efficient enough powder burn to produce more consistent chamber pressures. So from your selection of powders, I would lean towards using faster burning than Unique/Power Pistol for your match loads. Exception I found is if your powder charge used is at mid to high range load data, BE-86/Power Pistol/WSF have shown to produce accuracy while slower burning powders required near max/max load data to produce optimal accuracy.
Factory ammunition often needs to meet certain velocity requirements. With 115 gr FMJ/RN, I found that I need to push to high to near max load data to optimize accuracy while with 124 gr FMJ/RN (with longer bullet base), I can produce accuracy even at mid range load data. With W231/HP-38 and 115 gr FMJ/RN loaded to 1.130"-1.135" OAL, I get reliable slide cycling around 4.5 gr (Glocks with new RSA) and get accuracy at 4.6 gr and use 4.8 gr as my reference 9mm load for slightly greater accuracy that is comparable to Winchester white box.
But based on my testing, I have found WST/Bullseye/Titegroup to produce smaller groups than W231/HP-38 with IMR Target showing real promise of smaller groups.
While 45ACP (lower pressure high volume case), Shooting Times did bullseye match powder comparison 25 yard Ransom Rest testing using 185 gr JHP (Nosler, Zero, Hornady, Sierra) and N310, N320, 700-X, Clays, Titegroup, Bullseye, W231, and WST using -
https://www.shootingtimes.com/editorial/loads-for-the-bullseye-shooter/99418#:~:text=The powders used by Bullseye,45 ACP.
"Summing it up, all the powders produced nice groups from my pistol, though some were more consistently smaller than others. The overall average of the 55 groups fired was 1.90 inches. My gun showed preferences for some powders and specific loads, which is no surprise because most guns do.
Few of us will go to the efforts of some Bullseye shooters who might only use new brass, trimmed to the same length, and so on. The small gain in accuracy might be very important to a competitive shooter who is trying to squeeze every bit of accuracy from his or her ammunition. A reduction in group size of a half-inch at 50 yards is a big gain for them, but most shooters won't be able to tell much difference in their non-match pistol at the usual distances they shoot. Simply using a bullet and powder combination that produces excellent accuracy might be all they need to noticeably improve accuracy. An accurate bullet paired with the right powder (and possibly primer) can do wonders for shrinking group size."
But keep in mind that with large volume case 45ACP, semi-auto testing is essentially determining which powder does better with air gap between flash hole and powder granules (Top down powder burn) compared to small volume case 9mm where depending on powder and charge used, you may have powder granules covering the flash hole for powder rear to forward burn.
I hope this helped.
