Load Development

[TheDude8102]

Headed out to Atturbury today to test different seating depths...After some number crunching I think it is clear what seating depth my rifle likes.

 

[AmmoManAaron]

What rifle?
Caliber and load details?

 

[TheDude8102]

Shooting this out of my Tikka t3x CTR (20" barrel).

Bullet: 140gr ELD-M
Powder: H4350
Brass: Lapua
Primers: CCI #450

I plan on loading up some more at 0.02" OTL everything the same just to confirm. I feel like a single 5 shot group is not enough to go off of with those results but still made me happy to see.

 

[jrh84]

Headed out to Atturbury today to test different seating depths...After some number crunching I think it is clear what seating depth my rifle likes.

View attachment 87303

Did the lowest SD's correspond with the best groups on the target?

 

[76Too]

Shooting this out of my Tikka t3x CTR (20" barrel).

Bullet: 140gr ELD-M
Powder: H4350
Brass: Lapua
Primers: CCI #450

I plan on loading up some more at 0.02" OTL everything the same just to confirm. I feel like a single 5 shot group is not enough to go off of with those results but still made me happy to see.

I’ll bite...why use a magnum primer for a bolt action (6.5cm I think from your speadsheet?)

...better ignition?

...just compensating? I used to know a guy that would over-pay and buy magnum condoms because he actually thought they were bigger (they’re not).

i’m envious of your spread sheet and really need to start getting serious about organizing my data. I’be got all my pet loads memorized, but just branched out into a couple different calibers and need to start getting this stuff down digitally (or at least on paper) before it’s pushed out of my head and replaced with coronavirus propaganda.

 

[Contender]

Can't speak for the OP but I have a few loads that don't show mag primers in the book but I get way better accuracy with them. One is a 22 hornet, most will say a mag primer ruins accuracy in that small a round but with IMR 4227 my groups are impressively smaller.

 

[TheDude8102]

Did the lowest SD's correspond with the best groups on the target?

Yup it did, about a .4" group at 100 yards for this group. However, I had 2 or other groups about that size as well but they all correlated to my strings with lowest ES and SD.

 

[TheDude8102]

I’ll bite...why use a magnum primer for a bolt action (6.5cm I think from your speadsheet?)

...better ignition?

...just compensating? I used to know a guy that would over-pay and buy magnum condoms because he actually thought they were bigger (they’re not).

i’m envious of your spread sheet and really need to start getting serious about organizing my data. I’be got all my pet loads memorized, but just branched out into a couple different calibers and need to start getting this stuff down digitally (or at least on paper) before it’s pushed out of my head and replaced with coronavirus propaganda.

From what I have read, if using a small primer on 6.5 Creedmoor it is recommended to use either magnum primers or bench rest primers to aid in better powder ignition uniformity. This isn't really an issue with a large primer since there is a larger flash hole.

Now, have I tested this theory or had any issues with regular primers? Nope. But the logic made sense to me and I have had no issues with magnum primers. Some say that magnum primers are less consistent but I have only seen the opposite being true.