The 22 creedmoor thread

[SouthPaw]

Was that an 8 twist? Preferred has a tikka prefit on sale but it’s a sammi throat and 1:8 twist. I’m sure 77tmks are enough for anything I will do, but don’t want to loose the opportunity to run the new 88s because of not enough twist

It was a 7.5 twist.

 

[Stocky]

At 300' of elevation and near freezing, I'd be willing to bet you were at a negative density altitude. Using 35⁰f and 30.5 inches of mercury at 300' of elevation you show a density altitude of -1228'. That makes it tough on any bullet in the marginal zone.

Jay

For sure 4dof has the SG around 1.09 so it shouldve been just been stable but obviously an assumption in the calculater somwhwere was a bit off. Its a situation that can occur to people hunting at our near sea level in winter.

Its the risk of running marginal stability. I could have ran it most of the time but it could also fail me in the field too. Im sure Alaska and a few places in north America run into those conditions or worse. And I would have to think some significant BC degradation is occurring before complete failure.

It was more just saying 8 twist is marginal and isn't always safe at sea level. I hunt at sea level in the winter relatively often and a cold morning could have them tumbling.

We are a bit unlucky in that we usually start our hunts between 0-2000ft but then often hunt the alpine between 4500- 6500ft. So need stability at both ends just in case. Luckily we dont get the extreme cold. I usually hornady for SGs at -5c @ 0 feet and try stay above 1.25ish to allow some fudge factor. Thats proved to be safe for any situations ive tried so far. Its just worth checking your worst case hunting scenarios usually the coldest and the lowest elevations.

Some of you high desert dwellers are probably pretty sweet im jealous of being at 5-6000ft plus as a base.

 

[TimberHunter]

For sure 4dof has the SG around 1.09 so it shouldve been just been stable but obviously an assumption in the calculater somwhwere was a bit off. Its a situation that can occur to people hunting at our near sea level in winter.

Its the risk of running marginal stability. I could have ran it most of the time but it could also fail me in the field too. Im sure Alaska and a few places in north America run into those conditions or worse. And I would have to think some significant BC degradation is occurring before complete failure.

It was more just saying 8 twist is marginal and isn't always safe at sea level. I hunt at sea level in the winter relatively often and a cold morning could have them tumbling.

We are a bit unlucky in that we usually start our hunts between 0-2000ft but then often hunt the alpine between 4500- 6500ft. So need stability at both ends just in case. Luckily we dont get the extreme cold. I usually hornady for SGs at -5c @ 0 feet and try stay above 1.25ish to allow some fudge factor. Thats proved to be safe for any situations ive tried so far. Its just worth checking your worst case hunting scenarios usually the coldest and the lowest elevations.

Some of you high desert dwellers are probably pretty sweet im jealous of being at 5-6000ft plus as a base.

Doesn’t 4Dof want a 1.4/1.5 SG to be considered stable?


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[Stocky]

Doesn’t 4Dof want a 1.4/1.5 SG to be considered stable?


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Nope a minimum of 1 to fly point first. They recommend an minimum of 1.4 in ambient conditions to allow for low temps and low altitudes and some assumption error.

https://static.hornady.media/site/hornady/files/ballistic/hornady-4dof-technical-paper-v2.pdf

 

[TimberHunter]

Nope a minimum of 1 to fly point first. They recommend an minimum of 1.4 in ambient conditions to allow for low temps and low altitudes and some assumption error.

https://static.hornady.media/site/hornady/files/ballistic/hornady-4dof-technical-paper-v2.pdf

So safe to say stability of 1.09 is no bueno…


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[huntnful]

First 10 shot group shot after a pressure ladder test. My best 10 shot group that I can remember. .486" PBB 18" 42gr. H4831sc under a 77 tmk. I felt a slightly heavier bolt lift on shot 10, so I am going to back it off a grain or 1.5 and hope it continues to hammer. Barrel only has 50 rds on it Avg of 10 shots was 3052 fps.
View attachment 993583

I can’t even hold that steady haha. Epic!

 

[Stocky]

So safe to say stability of 1.09 is no bueno…


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Atleast in this barrel with that bullet at ~2600fps. It was stable when first checked at the same range but during the day guessing about 15 degrees C. Came back at 5am the next morning in a decent frost and no go. Even at 60f ish I would have only been 1.15 stability so was definitely on a fine line. Apparently the Tikka 8 twists are a bit slow too.

@pathnz has a Mullerworks barreled 8 twist 223 and also found 88s unstable in his rifle. I guessing based on his location hes also very near sea level. And that rifles an absolute hammer. Hate to know how many animals its killed. Its what i wish one of my 223s would behave like.

 

[The Guide]

For sure 4dof has the SG around 1.09 so it shouldve been just been stable but obviously an assumption in the calculater somwhwere was a bit off. Its a situation that can occur to people hunting at our near sea level in winter.

Its the risk of running marginal stability. I could have ran it most of the time but it could also fail me in the field too. Im sure Alaska and a few places in north America run into those conditions or worse. And I would have to think some significant BC degradation is occurring before complete failure.

It was more just saying 8 twist is marginal and isn't always safe at sea level. I hunt at sea level in the winter relatively often and a cold morning could have them tumbling.

We are a bit unlucky in that we usually start our hunts between 0-2000ft but then often hunt the alpine between 4500- 6500ft. So need stability at both ends just in case. Luckily we dont get the extreme cold. I usually hornady for SGs at -5c @ 0 feet and try stay above 1.25ish to allow some fudge factor. Thats proved to be safe for any situations ive tried so far. Its just worth checking your worst case hunting scenarios usually the coldest and the lowest elevations.

Some of you high desert dwellers are probably pretty sweet im jealous of being at 5-6000ft plus as a base.

I ran the numbers at one of my hunting spots that is about 4000' altitude when the temp was 10⁰f after a hard snow fall. The DA ended up being -170'. Conditions like that are the reason why I haven't changed 100% to little guns for year round hunting. Big bullets going fast are the best way to overcome a negative Density Altitude.

Jay

 

[TimberHunter]

I ran the numbers at one of my hunting spots that is about 4000' altitude when the temp was 10⁰f after a hard snow fall. The DA ended up being -170'. Conditions like that are the reason why I haven't changed 100% to little guns for year round hunting. Big bullets going fast are the best way to overcome a negative Density Altitude.

Jay

I must be missing something. 4000’ at 10’degree is coming up with about 1600’ DA on this chart?


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[The Guide]

I must be missing something. 4000’ at 10’degree is coming up with about 1600’ DA on this chart?


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Shooter calculated it based on local weather station information. I did not calculate it but the drops were spot on and the elk died @ 420 yards.

Jay

 

[ChrisAU]

Nothing of real substance to add, though I’m getting to where I just don’t know why I even own anything else outside of my twin 22CMs. So far this hunting season after switching to my 77TMK hand loads in my day rifle I have a Muley buck, a whitetail buck, whitetail doe, a large boar hog, and a coyote. Total distance traveled by all 5 is 0 yards. To be fair the doe, hog, and yote were dome checked but both bucks were high shoulder and DRT. The next month will hopefully bring 1-4 more whitetail bucks and probably a doe or 3 and hogs if the opportunity presents itself.

 

[mtnbound]

I ran the numbers at one of my hunting spots that is about 4000' altitude when the temp was 10⁰f after a hard snow fall. The DA ended up being -170'. Conditions like that are the reason why I haven't changed 100% to little guns for year round hunting. Big bullets going fast are the best way to overcome a negative Density Altitude.

Jay

Curious, what is your dial for the 420y shot at 4000 DA? What did Shooter say it was at -170?

 

[HuntHarder]

At that range, i doubt it was any more than .25-.50 moa difference.

 

[Pickettpuncher]

Looking for some feedback. I think my barrel is slow but maybe it’s not. 18” pbb. Truly struggled getting over 3k with h4350 and an 80gr eldm. Got some n560 and at 45gr I’m at 3150. Does that sound close to right. I’m ok at 3150, just wanting to see what others have seen.

ETA…. I have roughly 140 rounds thru the barrel.

 

[B_Reynolds_AK]

Looking for some feedback. I think my barrel is slow but maybe it’s not. 18” pbb. Truly struggled getting over 3k with h4350 and an 80gr eldm. Got some n560 and at 45gr I’m at 3150. Does that sound close to right. I’m ok at 3150, just wanting to see what others have seen.

ETA…. I have roughly 140 rounds thru the barrel.

What was your powder charge of H4350?
I was getting 3170 fps from 80’s out of an 18” ACE barrel using H4350.

 

[Smokinyotes]

Looking for some feedback. I think my barrel is slow but maybe it’s not. 18” pbb. Truly struggled getting over 3k with h4350 and an 80gr eldm. Got some n560 and at 45gr I’m at 3150. Does that sound close to right. I’m ok at 3150, just wanting to see what others have seen.

ETA…. I have roughly 140 rounds thru the barrel.

With 45 gr of N560 and a 77 grTMK I’m getting 3414 with a 24” tube.

 

[Pickettpuncher]

What was your powder charge of H4350?
I was getting 3170 fps from 80’s out of an 18” ACE barrel using H4350.

38.5

 

[Pickettpuncher]

With 45 gr of N560 and a 77 grTMK I’m getting 3414 with a 24” tube.

So I’m probably right where I should be with an 18

 

[Smokinyotes]

Should be pretty close

 

[HuntHarder]

Damn! My 18" is gonna top around 3000 fps* with a 77tmk using 4831sc. At 3100ish, I saw decent pressure. I might need to grab some N560