frogfoot

CCI 450 and federal

# thanks, but thats still a 5 hour round trip from where I am. and Hazardous delivery charges are extortionate

I was thinking I may have to batch the brass, and I think I'll try the Murom KVB-223M primers if I can find any in this neck of the woods. Anyone know of a stockist in the South West?

Your spot on with the ES/SD. Currently I haven't batched brass (I don't have an accurate digital scale and can't face weighing each one on a balance beam yet). Brass is deprimed using Redding universal deprimer with small pin, wet tumbled in SS media, Annealed using a 'Reloader Brass annealer' Body resized to bump the shoulder 1 to 1.5 thou, Trimmed and chamfered with Lee quick trim ( currently only chamfering as cases are still below SAAMI max) Then Neck sized using Lee collet die (with turned down depriming pin). This give 2 thou of tension. Bullets are seated with Redding Comp seating die to 30 off the lands. Charges are weighed on RCBS M500 scale. Primers are seated with Sinclair hand tool. Tom

Well I got out today for an hour and shot a few groups. Working on my technique, (this is my first full bore target rifle). The best two groups were both 44 gn, one virgin brass one once fired. both are 10 shot groups, ES and SD were disappointing, Virgin brass 44gn MIN 2693 MAX 2748 AVE 2715 SD 14 ES 55 Once fired Brass 44 gn MIN 2695 MAX 2738 AVE 2715 SD 12 ES 43 The Black stickers in the center are 10mm, the groups were shot at 100 Yds. Pretty happy so far I'm off to the 600 Yd range on Saturday. I'm Sure the ES will cause me some problems at that range. Tom

Yesterday I started my own load development with my new Tikka T3 TAC A1 in 6.5 Creedmoor with virgin Lapua SR brass, 139 Lapua Scenars, CCI450 primers and RS62. I used my new magnetospeed v3 to gather velocity data, focussing on finding a velocity plateau from where I can tinker with OAL to fine tune precision. The rifle had fired 20 rnds of factory to start breaking it in and for me to get a feel for normal levels of recoil, extraction etc. Brass was chamfered and then neck sized using Lee collet neck sizing die (with decapping pin turned down) and bullets were seated to an OAL of 2.853 (CBTO 2.304) to be 30 thou off the lands in my rifle using a Redding Competition seater. (This gave very good concentricity all less than 1.5 thou) I worked up from 41.6 to 44.6 in 0.3 gn steps and then from 44.8 to 45.2 in .2 gn steps then added one for luck at 45.3gn There were no signs of pressure, easy bolt lift, no cratering/blanking and only moderately flattened primers with only a barely discernible difference between 44 and 45.3gn (image of 45.3gn primer is shown below) The groups were all pretty respectable with half being <0.5 MOA and the rest < 1 MOA, but this was not the purpose of this exercise, I was time limited so could not let the barrel cool as much as I wanted between strings, and I could have put more effort into better technique. I plotted the velocity data along with SD and ES from the tests in Excel which seem to concur with the consensus that 44gn is a good node (in virgin SR Lapua brass.) ES and SD were a bit all over the place, Hopefully these will come down with a couple of fire formings and weight batching of the brass. I noted that Velocities were slightly higher than those reported by VarmLR, possibly due to a faster barrel. Tom Primer from 45.3gn load

Thanks for the reply Laurie, that is interesting to know about the SR magnum vs standard primers. So the question remains what could have caused the tight bolt lift and ejector marks? VarmLR are you FL resizing, or just neck sizing? If only neck sizing perhaps om the 3rd firing the case has expanded to the point , and work hardened enough that it doesn't contract back enough for a smooth extraction . Tom

I find this an interesting point. It seems counterintuitive for the magnum primer to provide less pressure, could it be that the 2F fired brass was not bumped back to the same length as the 1F brass, causing a tighter fit in the chamber before firing? However, I would expect to see the non magnum primers to show signs of cratering as they generally have a thinner cup, maybe Laurie would have an insight as to what is going on here Tom

VarmLR, is that last value correct? (46 grains) It seems like a very large step, or was it supposed to read 44.6?