Interesting (and a bit odd) load development outcomes

dodgyknees

Well-Known Member
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.
 
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25 Sharps

Well-Known Member
Have you tried shooting a group letting the barrel completely cool between each shot to see if the barrel heating can be ruled out?
 

mchughcb

Well-Known Member
I use the same bullet but I use 40gr of 2209. I have found 2209 to provide very consistent sub MOA results for bullet weights over 80gr. Give it a go, I think you will find it gives you good accuracy. Won't solve the one powder for everything though.
 

dodgyknees

Well-Known Member
What fill ratio does 33gr of AR2206H give you? Regards JCS
Good question and one that sent me on a voyage of new discovery.

I worked out the load density for the 32gr AR2206H charge (the mid range of my test), using some old software I had. It returns a value of 72% using some reasonably accurate measurements for the boat tail of the Sierra 1560. This seems a bit low I guess...

I used the ADI load data manual to derive the powder weights for my load development. They don't quote the exact bullet I was using, so I used the closest type which was the Speer 100gr boat tail spire point, a pretty close match I thought. The start / end value of powder weights are 31 / 33gr AR2206H.

ADI quotes IMR4895 as the powder equivalent for AR2206H.

So when I cross reference with the Sierra book, I see they quote a powder range of 31.6 to 36.2gr IMR4895 for a velocity range of 2500-2900fps. That's quite a difference.

If I was to use the max Sierra powder weight, the load density (fill ratio? same thing?) increases to 81%.

And looking at the question below from mchughcb, his 40gr would give a load density of 90%.

As a comparison my ultra accurate .223 load which reliably gives me very tight groups all the way out to 300m: load density 99%.

So now I'm wondering if I should carefully increase the load of AR2206H to the IMR4895 levels quoted by Sierra on the assumption that these two powders have very similar burn rates. They are #171 and #178 on the reloadersnest Powder Burn Rate Comparison.

Bottom line, is the fill ratio too low, and the velocity too low?


Have you tried shooting a group letting the barrel completely cool between each shot to see if the barrel heating can be ruled out?
I will next time. Because I don't exactly get the chance to 'warm up the barrel' when I'm about to shoot the one deer I really want, eh? I need to reliably know what it does when its dead cold.


I use the same bullet but I use 40gr of 2209. I have found 2209 to provide very consistent sub MOA results for bullet weights over 80gr. Give it a go, I think you will find it gives you good accuracy. Won't solve the one powder for everything though.
I will definitely look at that option, are you also using a .243 with a 1 in 10" twist? Don't suppose you've been able to chrono your load by any chance. It's quoted by ADI as being a little shy of 3000fps which would be good to achieve with reliable accuracy.
 
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plumber01

Well-Known Member
I think you may have answered your own question, usually i find if you can have the case near to full you get more accuracy, and usually fast is better than slow, try to use a powder giving near 100% at max velocity might help. good luck
 

dodgyknees

Well-Known Member
Picked up some ADI 2209 today which should give me up to 90% load density, so will load three weights with some new Lapua brass tomorrow and head out back to see what happens next. Thanks for the suggestions so far.
 

dodgyknees

Well-Known Member
Thanks to the forum members who volunteered ideas / advice, today's load development yielded a very satifying outcome. The red bullseye is 40mm diameter.


I switched to ADI AR 2209 and started at 38gr and increased in 0.5gr increments.


Load: 40gr ADI AR2209, C.O.A.L. 2.645", Sierra Gameking 100gr BT Spitzer. This C.O.A.L. is a soft touch on the lands, no neck crimp.





I was ****ed off to the max with shot #5, which I pulled left with poor exhale / squeeze timing.


Here's an interesting photo of what happens if you make small changes to some of the variables:


Load: 41gr ADI AR2209, C.O.A.L. 2.625", Sierra Gameking 100gr BT Spitzer. This C.O.A.L. is 0.020" back from the lands.

[note: earlier I mistakenly entered 39gr for the powder weight, sorry about that]




I was a bit over it after the 39.5 gr group, thinking it was gonna be a case of poor stabilisation. But then at 40gr, suddenly the group tightened up and job done. So there's a sweet spot for sure, and that's where I'll stick.
 
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mchughcb

Well-Known Member
Good to hear. 2209 is my main powder 243 to 416. Does well in all of them with the heavier bullets.
 

Muir

Well-Known Member
You dropped a grain of powder and seated the bullet .020" deeper and had a shift in POI of 1.5" down and right two inches, with the groups doubling in size. I wouldn't begin congratulating yourself just yet: That is not a happy load for your rifle. How many groups like the 40 grain illustrated above did you get?? ~Muir
 

dodgyknees

Well-Known Member
You dropped a grain of powder and seated the bullet .020" deeper and had a shift in POI of 1.5" down and right two inches, with the groups doubling in size. I wouldn't begin congratulating yourself just yet: That is not a happy load for your rifle. How many groups like the 40 grain illustrated above did you get?? ~Muir

Sorry Muir, I think there's a misunderstanding in play here, which is totally my fault as I forgot to mention a scope adjustment AND I posted the wrong powder weight for the second photo...

Sequence of loads shot was 38, 38.5, 39, 39.5, 40gr, 41gr. At 40gr the group tightened up markedly. The subsequent 41gr group was very poor.

The 41gr load replicates the Hornady load for 100gr bullets with Win 760, which is the AR2209 powder equivalent. Hornady specifies a shorter C.O.A.L. by 0.020". It was the only one with the bullet seated back from the lands.

Then I went back to the shed and loaded more 40gr cartridges, made a scope adjustment to improve the zero, then shot another 5 shot group which is the first photo from the earlier post.

So the second photo shows the outcome of the 41gr load, not 39gr, apologies again. I've edited the earlier post to reflect this. (Note the handwritten load data on the target).

No overpressure signs for any of the higher loads.

So yes the 40gr outcome is repeatable and I'm happy that I've got the 100m accuracy required to start testing bullet drop in 50 meter increments so I can learn the BDC reticle for quick decision hold over shots in the field.
 
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ChesterP

Well-Known Member
It would be worth-while now playing with seating depth. There's better precision and accuracy to come. I would be unhappy if not managing 0.5moa at 100 yds consistently, even if moa was adequate for purpose. Seating depth variations affect pressure, load fill ratio and (very marginally) barrel time. All of these things can affect consistency and accuracy. I found that by increasing seating depth for one of my .223 loads to 100 thou (!) from 15 thou, the groups went from moa to 0.25moa. I must admit, the best groupings for all my calibres seem to be case full, slightly compressed or close to full. Case full is meant to propagate a more even and consistent burn, hence better groupings.
 

JamieDenny

Well-Known Member
Really interesting post.
I use imr4064, 35.3gr, 87gr hornady vmax.
What speed do you get over the chrono?.

Sent from my D5803 using Tapatalk
 

dodgyknees

Well-Known Member
Really interesting post.
I use imr4064, 35.3gr, 87gr hornady vmax.
What speed do you get over the chrono?
I don't have a chrono or access to one, I'm just going on load manual assumed velocity less 40fps for every inch less that the quoted barrel length as mine is 20".

Used the .243 for the first time on game this past week - feral goats - with devestating consequences... for the goats and my ears until I remembered to use my earplugs. Both the Hornady VMax 75gr and Sierra Gameking 100gr did the job out to 250 yds, the longest shot taken in hilly terrain. The VMax were extremely accurate and remarkably explosive. The Gamekings punched straight through the torso and when connecting with a shoulder on the way in knocked the goats clean off their feet. Nothing got up, not so much as a bleat.

I've picked up some Sierra ProHunters in 100gr to see if the flat base brother to the boattail Gameking will make a tangible difference to accuracy. Being a shorter bullet the stability calculators like it more for this rifle than the longer boattails. Plan to load some up tomorrow and test assuming the infernal wind drops.

On a slightly different matter, sorry I know its a complete diversion but.... On same trip shot a good sized red hind at 30yds with the .308 T3 using a 168gr Nosler Ballistic Tip with a fairly hot ~2750fps load. Shot was from about 16h30 assuming the deer's head is facing 12h00, downhill at -15deg. In through the upper right rear rib cage, towards left shoulder. Deer jumped about 4ft, ran 10yds to the left and then dropped stone dead in a heap. On inspection there was just a tiny entrance wound, and no exit wound, not a mark. Gutting it revealed hydrostatic shock on a level I've never seen before. Utter mush. Liver, lungs, various other bits like half set jelly. Bullet had smashed left shoulder blade but not one bullet fragment was found during skinning. Where the hell did it all go? Meat recovery was high, some loss on left forequarter but not much. First time I've used this bullet and bugger me it was effective but I really don't like not have an exit wound.

Then tried the same load on two medium pigs, head shots at 75yds, the pigs were spun around and dropped like rag dolls, which is a feat as they are heavy little buggers. Instant death and explosive damage from a bullet I can't make up my mind about... A real lesson for me in projectile selection for a specific job.
 

mchughcb

Well-Known Member
Ballistic Tips are okay until you try Woodleigh. You are right, match the projectile selection for the job.
 

dodgyknees

Well-Known Member
It would be worth-while now playing with seating depth. There's better precision and accuracy to come. I would be unhappy if not managing 0.5moa at 100 yds consistently, even if moa was adequate for purpose. Seating depth variations affect pressure, load fill ratio and (very marginally) barrel time. All of these things can affect consistency and accuracy. I found that by increasing seating depth for one of my .223 loads to 100 thou (!) from 15 thou, the groups went from moa to 0.25moa. I must admit, the best groupings for all my calibres seem to be case full, slightly compressed or close to full. Case full is meant to propagate a more even and consistent burn, hence better groupings.
Some minor tweaks to the load has resulted in a reliable 0.5MOA group at 100yds. Switched to Sierra ProHunter 1540 flat bases, slightly shorter than the Gameking 1560 boat tails for the same weight.

Projectile seating depth is set to a soft touch on the lands. The cases are fire formed with a neck resize only. After seating, a moderate neck crimp.

The first two photos is the first ProHunter group shot before the scope was re-zeroed, the scope having been swapped out, plus addition of suppressor. We're shooting off the back of the ute (pickup), standing, using a bipod with a small rear Cardwell bag supporting the grip. The target squares are 0.5":








After setting the zero, me and the wife did some more "real" groups, by hopping out of the vehicle, quickly setting up the rifle on the bonnet (bipod only, no bag support on the grip) and shooting a quick three shot group. Thus mimicking what we do in the field when culling goats or coming across a pig or deer. Both shooters delivered reliable 1.0MOA - 1.5MOA groups at 100yds on a windy day, with just the bipod, a hot rifle and a minimum of time:





The ProHunter load is marginally more accurate in this rifle than the Gameking 1560s, if you are thinking in benchrest terms, but the animal on the receiving end of either pill isn't going to know the difference. The stability calculators deliver a 'stable' outcome for the PH, and a 'marginally stable' outcome for the GK, but in reality they are quite close. Bottom line is that the lower BC / shorter OAL ProHunter is a slightly better pill in the 1:10" twist barrel at the 100gr weight.

Nothing has been done to the rifle other than the addition of a DPT over barrel suppressor.

So that's the end of the story. This Howa 1500 with the Hogue stock is a cheap but reliable rifle that has delivered (for me at least) outstanding performance once we worked out the loads, with a bit of help... At the 100gr weight, cheap Federal factory ammo was very average, then low fill ratio hand loads with my normal powder were rubbish. A switch to a slower burning powder and a high fill ratio showed promise but there was still some work to do around exact powder weights, seating depths and then case prep and crimping.

Also there's been a lot of work on our shooting positions, in particular the amount of downward force applied by the left hand to the forend just behind the bipod. I think bipod "bounce" has potentially played quite a big role in perceived inaccuracy early on, especially shooting off the ute and experiencing the odd flier. Now our work is on longer range tests out to 500yds to learn the Weaver scope EBX reticle.

I'm really pleased with the outcome and the help on this forum got me over the line. Other forums were very quick to rubbish the "cheap rifle" and "crap stock" and "bipod screw hitting the barrel" and various other misinformed rubbish that these keyboard warriors read elsewhere and assume to be truths, to be repeated elsewhere at will. All good here on the farm... The goats are very, very scared of this cheap .243.
 
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