L Primer choice
Primers affect pressure, we have some data on that. My Jacketed Bullet Test data on primers is messy at best, and far from conclusive. My experience is that primer choice may affect accuracy, but the effect is small; so it’s in “List 1”.
frnkeore:” I try several primers with everything I shoot and after 36 years of competitive shooting, I KNOW that they make a difference with many powders but, some powders are not sensitive to primes, such as 4227. Many ball powders that I have used are.”
Tom Acheson: “In each of the past and present chambering’s that I’ve had on my XP-100, I tried both the FC 205M and R-P 7 1/2 small rifle primers. In each comparison, the Remington primers shot smaller groups. The differences were not huge but enough that I decided on the primer that I did. These chamberings include 30 BR, 30 PPC, 30 Silhouette and 6.5mm TKS. Powders included Vit., RE-7, SR 4756, 4198, 5744, 4166, and SR 4759 and few others I can’t immediately recall.
Jumping over to BPCR with black powder, I tried the FC 210M, FC -150 large pistol and CCI BR-2. All testing was conducted @ 200-meters, off the bench. Groups were 10-rounds. After all the testing and several Scheutzen match entries, I’ve concluded that THIS rifle and brand/grade of black powder preferred the CCI BR-2 primers.”
Jacketed Bullet Test data on primers-223 Rem. This is for ALL groups shot, with 3 jacketed bullets, some cast bullets, and 7 different charges of powder with each jacketed bullet.
IFFLAND STEVENS M12 OLD SUM
AVG” #GRPS AVG” #GRPS AVG” #GRPS AVG” #GRPS
CCI 1.123 82 1.108 110 1.006 42 1.095 234
FED 1.627 58 1.305 5 1.602 63
WIN .895 19 1.125 6 .950 25
1.183 322