Bullet Grouping Difference

With any component change a node can and most likely will shift slightly whether combustion or with harmonics as I believe you are seeing here.
Lapua are typically secant ogive whereas the sierra’s are tangent.

Re-tune the load by starting with an incremental charge test followed by a seating adjustment.

Re-work your load up for the different bullet. The SMK give me sub MOA.

I think that it takes more than 1 five shot group to make any definitive judgements. SMK's are not junk bullets. Maybe a tweak to your load would tighten the group, or maybe something else caused that string to open up. Shoot a couple more groups to verify.

Laphroaig said:

toddnic said:

Both 5-shot groups were from a 223 Wylde with a 20-inch Faxon heavy barrel ... 25 gr Ramshot Tac ... sub-MOA 69gr Lapua ... 2 MOA 69 gr SMK

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I think that it takes more than 1 five shot group to make any definitive judgements ... maybe something else caused that string to open up. Shoot a couple more groups to verify.

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I agree. If Lapua group was shot first, barrel warming up/fouling/etc. could have affected SMK group.

When I am testing new bullet/powder and initially identify accuracy trend/nodes, I always conduct subsequent range trips to verify accuracy before designating a load "accurate" as there are many reloading and shooting variables.

As Laphroaig suggested, I think further range testing will reveal more information. Perhaps shoot SMK groups first on the next range trip?

How was accuracy at different powder charges around 23 - 24 gr range?

BTW, Hodgdon load data - https://www.hodgdonreloading.com/reloading-data-center

• .223 Rem 69 gr Sierra HPBT Ramshot TAC COL 2.260" Start 21.9 gr (2,671 fps) - Max 24.3 gr (2,921 fps)

Blue68f100 said:

Re-work your load up for the different bullet. The SMK give me sub MOA.

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Same here. In my Ruger American Ranch, I typically get .5 MOA or less groups with 69g SMK and Varget. Other powders don't necessarily work as well for me.

LiveLife said:

toddnic said:

Any thoughts or recommendations?

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barrel warming up ... there are many reloading and shooting variables ... shoot SMK groups first on the next range trip

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Since both groups were shot with the same barrel, if SMK rounds were chambered long enough to warm up the powder charge, temperature increase could be another shooting variable and why I suggested shooting SMK group first on next range trip.

Blue68f100 said:

Re-work your load up for the different bullet. The SMK give me sub MOA.

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Was separate powder work up done for SMK?

toddnic said:

Hard to believe that there would be that significant of a difference.

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Not a bit, and a single 5 shot group only barely qualifies as an anecdote. Repeat each recipe 2 or 3 more times, then you will have a small amount of data.

A 0.5-2 MOA variation between bullets isn't a bit surprising.

edwardware said:

toddnic said:

223 Wylde 20-inch Faxon heavy barrel

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A 0.5-2 MOA variation between bullets isn't a bit surprising.

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My 18"/20" heavy barrel .223 Wylde ARs increase group size as barrels warm up. After warm up, groups can hover around 1+ MOA depending on ammunition.

Seriously here, expecting two different brands of bullets to shoot the same just because they ended up weighing the same is a little misguided. They both have different makeups and that alone will usually result in different results. Different compositions of gliding metal jacket and/or thickness of same, shape of bullet, alloy of core, all can be a game changer. Add to that those differences can react to barrel twist differently and that adds up to seperate load workups and LOTS of cold barrel testing to get a reasonable level of confidence in your results. Then change the propellant and start over again. It usually takes me 400-500 same lot bullets to find what I want for an accurate load. Just sayi'n.

toddnic said:

I had an interesting difference in two groupings of bullets yesterday. Both 5-shot groups were from a 223 Wylde with a 20-inch Faxon heavy barrel. Sizing was a Redding S-Die with a .244 bushing. The powder was 25 gr Ramshot Tac. CCI small rifle primer. The sub-MOAView attachment 1087571 View attachment 1087572 group was a 69gr Lapua. The 2 MOA group was a 69 gr Sierra Matchking. Hard to believe that there would be that significant of a difference. Any thoughts or recommendations?

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Looks like you have found a good powder and load for the Lapua bullet. What I would do now is experiment and try to find the powder/load that will give the best results for the SMK.

how far off the lands are those bullets?

murf

toddnic said:

Hard to believe that there would be that significant of a difference. Any thoughts or recommendations?

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Be happy or keep looking.

All part of the fun

A bullet is like a woman, you have to figure out what it wants for best performance. You can't treat them all the same and expect the best performance. One may want to run faster, or like a different seating depth.

Lapuas tend to like a longer jump. Looks like you found thier happy spot.
I would run the coal on those SMK out in 0.003 increments until you are within 0.010 of lands and see what happens.

All Sierra bullets are not alike in accuracy.

Shot in my Howa 1500 bolt action rifle:
Sierra #1355 55gr FMJ/BT gives me 1.15" 5 round groups @100 yards.
Sierra #1390 55gr BTHP gives me sub 1/2 MOA 5 round groups @100 yards.

In th 30-06 the 168gr Hornady match bullets produce better groups than 168gr Sierra MatchKings.

In the 30-30 the Sierra bullets are more accurate than the Hornady bullets, the reverse of above.

Those results may not be duplicated in your guns, it can also be the temperature, humidity or other outside influences changing the results but since you shot them back to back that's probably not the reason.

@toddnic, welcome to THR!

toddnic said:

Hard to believe that there would be that significant of a difference. Any thoughts or recommendations?

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Did you do any load workup for these or this is just the start? Any chrono data? Just curious.
If you did some workup, shot number aside, you got at least one load worth preserving, and another that needs more work.