Two new loads to develop, both using ADI AR2206H. I have a question that comes at the end of the post... first the data:
Range conditions: about 18 deg C with a medium variable wind blowing from behind at about 05h30 to 11h30 if you imagine the target sitting at 12h00.
Load #1 - varmint load
Cartridge: ADI twice fired brass, CCI primer, Nosler Varmageddon 55gr (17240), OAL 2.260" (0.02" off the lands)
Powder weights tested: 25gr, 25.5gr, 26gr AR2206H
Rifle: Tikka T3 Supervarmint in .223, 1:12" twist
Have owned this rifle for 4 years now and it's the most accurate I've ever had. Photos of load tests at 100m below:
View attachment 77566View attachment 77567View attachment 77568
Pretty happy with that. The third load (26gr) is the max load in the ADI load data book.
Load #2
Cartridge: Lapua brand new brass, Federal primer, Sierra Gameking 100gr SPBT (1560), OAL 2.640" (0.01" off the lands (see note below))
Powder weights tested: 31gr, 31.5gr, 32gr, 32.5gr, 33gr AR2206H
Rifle: Howa 1500 in .243 with 20" barrel, 1:10" twist
*Note* The COAL measured with the Hornady tool is 2.650" which is the same as the stated length for several of the 100gr hunting bullets (e.g. Sierra), Hornady is 2.630". But the Noslers are 2.680" and won't fit this Howa chamber (e.g. Partition, which normally would be a first choice pill). This means there's not much room to seat bullets back from the lands, assuming they fir ok in the first place.
This rifle is new. I broke in the barrel and zeroed the scope using Speer match bullets, mid range loads also using AR2206H, and was reasonably happy with the results. Photos of subsequent load tests at 100m below:
31gr and 31.5gr
View attachment 77569View attachment 77570
The first shot with 31gr was with a dead cold barrel and it was way off. Like, WTF??? Assumed shooter error and continued. Subsequent shots up to the end of the 31.5gr group were spaced about 2 minutes apart and the barrel was only ever mildly warm.
32gr, 32.5gr and 33gr
View attachment 77574View attachment 77572View attachment 77573
Then there's a fair gap in time to the start of the 32gr group, about 15-20 minutes, and the barrel is cold again. First shot - way off, unlikely to be shooter error this time, exactly the same stance, wind, etc as before. Then another three shots, with a 2 minute gap between shots and a mildly warm barrel, this yields reasonable grouping for 32gr which might just scrape 1 MOA at 100yds.
Subsequent groups (32.5gr, 33gr) follow with 2 minute gaps, and a mildly warm barrel. Reasonable, but not great groups.
So I'm a bit confused. Not had this before, usually groups with my hunting loads are pretty good, 1 to 1.5MOA, no outliers. This new .243 hunting load is only 'marginally stable' according to the Berger stability calculator, but there's no sign of keyholing and I've never had problems with this length/weight bullet in .243 before.
The soft points on these Gamekings are pretty variable. COAL is up and down by a fair bit, some of the soft points are a bit out of shape. But, with the exception the the two 'cold barrel' shots, the groups demonstrate that my medium game sized target is shot in the vitals and likely very dead, every time.
I need to eliminate these outlier shots. Where to start? Can it be related to the apparently short maximum COAL of 2.650"?
Any advice would be much appreciated. Don't really want to spend a fortune of different powders, bullets etc, if the obvious is right under my nose and I just can't see it... Thanks in advance.
Range conditions: about 18 deg C with a medium variable wind blowing from behind at about 05h30 to 11h30 if you imagine the target sitting at 12h00.
Load #1 - varmint load
Cartridge: ADI twice fired brass, CCI primer, Nosler Varmageddon 55gr (17240), OAL 2.260" (0.02" off the lands)
Powder weights tested: 25gr, 25.5gr, 26gr AR2206H
Rifle: Tikka T3 Supervarmint in .223, 1:12" twist
Have owned this rifle for 4 years now and it's the most accurate I've ever had. Photos of load tests at 100m below:
View attachment 77566View attachment 77567View attachment 77568
Pretty happy with that. The third load (26gr) is the max load in the ADI load data book.
Load #2
Cartridge: Lapua brand new brass, Federal primer, Sierra Gameking 100gr SPBT (1560), OAL 2.640" (0.01" off the lands (see note below))
Powder weights tested: 31gr, 31.5gr, 32gr, 32.5gr, 33gr AR2206H
Rifle: Howa 1500 in .243 with 20" barrel, 1:10" twist
*Note* The COAL measured with the Hornady tool is 2.650" which is the same as the stated length for several of the 100gr hunting bullets (e.g. Sierra), Hornady is 2.630". But the Noslers are 2.680" and won't fit this Howa chamber (e.g. Partition, which normally would be a first choice pill). This means there's not much room to seat bullets back from the lands, assuming they fir ok in the first place.
This rifle is new. I broke in the barrel and zeroed the scope using Speer match bullets, mid range loads also using AR2206H, and was reasonably happy with the results. Photos of subsequent load tests at 100m below:
31gr and 31.5gr
View attachment 77569View attachment 77570
The first shot with 31gr was with a dead cold barrel and it was way off. Like, WTF??? Assumed shooter error and continued. Subsequent shots up to the end of the 31.5gr group were spaced about 2 minutes apart and the barrel was only ever mildly warm.
32gr, 32.5gr and 33gr
View attachment 77574View attachment 77572View attachment 77573
Then there's a fair gap in time to the start of the 32gr group, about 15-20 minutes, and the barrel is cold again. First shot - way off, unlikely to be shooter error this time, exactly the same stance, wind, etc as before. Then another three shots, with a 2 minute gap between shots and a mildly warm barrel, this yields reasonable grouping for 32gr which might just scrape 1 MOA at 100yds.
Subsequent groups (32.5gr, 33gr) follow with 2 minute gaps, and a mildly warm barrel. Reasonable, but not great groups.
So I'm a bit confused. Not had this before, usually groups with my hunting loads are pretty good, 1 to 1.5MOA, no outliers. This new .243 hunting load is only 'marginally stable' according to the Berger stability calculator, but there's no sign of keyholing and I've never had problems with this length/weight bullet in .243 before.
The soft points on these Gamekings are pretty variable. COAL is up and down by a fair bit, some of the soft points are a bit out of shape. But, with the exception the the two 'cold barrel' shots, the groups demonstrate that my medium game sized target is shot in the vitals and likely very dead, every time.
I need to eliminate these outlier shots. Where to start? Can it be related to the apparently short maximum COAL of 2.650"?
Any advice would be much appreciated. Don't really want to spend a fortune of different powders, bullets etc, if the obvious is right under my nose and I just can't see it... Thanks in advance.
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