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22-250 AI

284winner said:
Post your results with the 7 twist and 75 Hornady. I had blow ups using my 7 twist with 75s. I had to jump to an 8 twist to entirely end the bullet blow ups. I now shoot the 75/80 ELDM bullets. They function flawlessly now. Hopefully you won't have the same issues. Not sure if it was the ratchet rifling or fast twist that causes the blow ups but guessing the 7 twist was too fast.
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Will do.
 
It really smacks that gong plate doesn't it!
In for the field report when you smack the first coyote or groundhog with that!

At 3:54 you mention the charge is 47 gr of Ramshot Grand, is it really that much?
I think the case capacity of the 22-250 AI is close to 47 gr H2O, but by the time you sink that 85.5 in there can there really be that much powder?
 
RegionRat said:
It really smacks that gong plate doesn't it!
In for the field report when you smack the first coyote or groundhog with that!

At 3:54 you mention the charge is 47 gr of Ramshot Grand, is it really that much?
I think the case capacity of the 22-250 AI is close to 47 gr H2O, but by the time you sink that 85.5 in there can there really be that much powder?
Click to expand...
Yes. However, my average H2O = 48.86gr

More details:

1. Chamber was long throated for the 80gr. Hammer HHT bullet. CBTO = 2.2285" , COL = 2.765"

2. Unfortunately, the Berger 85.5gr Hybrid and 90gr VLD are jumping too far. In the next video I produced, I shot at 100 yards and these bullet's groups were very disappointing.

For the 85.5gr Berger, CBTO = 2.169", COL = 2.760", jump = 0.0595". OBT = 1.206ms
I could try to tweak the depth, but the 100 yard groups were +3".

3. I did shoot the 68gr Hammer HHT, and they shot subMOA.

Here is a screenshot of my Quickloads for the 85.5gr Berger. Note: I used Ramshot Magnum, which at my current QL update, I do not have Ramshot Grand in the powder database.
 

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Bummer about the groups not working on the 85.5 Berger.

I'm not fully awake and can't recall... does the barrel have the twist for the 85.5?

I just did a wildcat in 20 based on the 22 CM case using Alpha brass cause I can't get Lapua 22-250 for the time being. My case capacity after the fireforming is about 53.5 grains of H2O.

I'll take another look at the 22-250 AI once I have these 20 cal barrels burned up, but that will be a while.

Good Luck and looking forward to the range reports.
 
RegionRat said:
Bummer about the groups not working on the 85.5 Berger.

I'm not fully awake and can't recall... does the barrel have the twist for the 85.5?

I just did a wildcat in 20 based on the 22 CM case using Alpha brass cause I can't get Lapua 22-250 for the time being. My case capacity after the fireforming is about 53.5 grains of H2O.

I'll take another look at the 22-250 AI once I have these 20 cal barrels burned up, but that will be a while.

Good Luck and looking forward to the range reports.
Click to expand...
No worries!

Yeah, the McGowan 28" 1:7 is plenty fast enough for the 85.5gr Bergers. Honestly, I am not super disappointed since I am am a hunter 1st and steel banger 2nd! LOL. The Hammer bullets are better designed to take game effectively versus the Berger target bullets.

I have reached out to Alpha about getting some of their 22CM brass to convert. The small rifle primer seems like a much better option once these Lapua large rifle primer pockets start opening up.
 
AP2020 said:
No worries!

Yeah, the McGowan 28" 1:7 is plenty fast enough for the 85.5gr Bergers. Honestly, I am not super disappointed since I am am a hunter 1st and steel banger 2nd! LOL. The Hammer bullets are better designed to take game effectively versus the Berger target bullets.

I have reached out to Alpha about getting some of their 22CM brass to convert. The small rifle primer seems like a much better option once these Lapua large rifle primer pockets start opening up.
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Blue Collar Reloading usually has the SRP Alpha brass in stock.

I have built 2 light weight rifles recently, 1 in 22-250 AI on a Kimber Montana and 1 in 22 Creedmoor on a 700. Both 1-7, 1 Lilja and 1 Pac-Nor. Both are cut to 22" and both shoot 88 ELD-M's at 3200 and shoot 73 ELD-M's very well. No bullet blow ups yet. I'm going to try to get an antelope with 68 Hammer HHT's at 3600 this year in the 700 and hunt deer with the Montana 22-250AI and 88 ELD-Ms. I've taken several deer and 1 antelope with the 88's already and I'm a fan. RL 17 works very well in both chamberings.
 
(3443x720)/7 = 354k RPM
(3421x720)/7 = 352k RPM

Not sure where the hard line is, but somewhere above 320k RPM is sketchy with the lead core bullets. Try slowing them down to 3100 fps or below and see if maybe the poor groups are due to over-speed?

Also, maybe slow the tempo and use a bbl cooler. These overbore designs get hot fast and maybe all that mirage was a hint that the bbl was getting too hot?

Those copper solids were impressive at 379k RPM and still working! I would stop there, till the $1 per bullet reminded me to keep working.... Can't wait to see the impact on those!
 
RegionRat said:
(3443x720)/7 = 354k RPM
(3421x720)/7 = 352k RPM

Not sure where the hard line is, but somewhere above 320k RPM is sketchy with the lead core bullets. Try slowing them down to 3100 fps or below and see if maybe the poor groups are due to over-speed?
Click to expand...

Could very well be. I did have Sam at McGowen Precision Barrel throat the chamber for the 80gr Hammer HHT's. My Stoney Point Comparator shows a jump of approximately 0.010". However, on the 85.5gr and 90gr Bergers the jump is about 0.059".

I will try to slow them down and see what happens. Honestly, I only have less than 100 bullets each of the Bergers, and my intentions were not to hunt with these bullets.

RegionRat said:
Also, maybe slow the tempo and use a bbl cooler. These overbore designs get hot fast and maybe all that mirage was a hint that the bbl was getting too hot?

Those copper solids were impressive at 379k RPM and still working! I would stop there, till the $1 per bullet reminded me to keep working.... Can't wait to see the impact on those!
Click to expand...

Indeed! However, I recently just put on a heat resistant shield and suppressor cover back onto my can. The blast chamber on this suppressor gets very hot.

Recently, I have produced future videos shooting the 68gr and 80gr Hammer HHT's at 612 yards, they are still shooting subMOA. So I am very happy with those results.

This week, I will be shooting 10% ballistic gel and capturing the impacts with my high speed slomo video camera!
 
I'm with a couple of others here, shoot to fireform. Always very accurate. Why waste the time and effort as the case isn't usually fully formed unless its getting a heavy load. To each his own though, no wrong way to do it in the end.
 
Update:

Since I have gleaned so much great information from 6mmbr.com over the years, it was time that I gave back! On my 22-250AI Video Playlist, I have added a link to this great forum!

6mmbr.png
 
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