250gr A Tip in a 308

[davidjoe]

For the amount of gusting wind with a constant hold, and the fact that this is only at 600 yds, (not newish barrel - the load is really more for 1,000), I’m happy. 200H would have grouped a little looser, especially in this long throat.

 

[Pinkes]

Why try the 250gr and not the 230gr?

 

[davidjoe]

Yesterday the 250’s registered 1,540 FPS at 1,000. The SD’s at the target were in the 8’s in each of 4 test relays, 2 with Palma brass and 2 with standard. The standard brass accuracy lagged about 10 points behind the Palma. My lower score with standard was confirmed by PJ who shot the 4th relay. Standard was loaded only .1 grains lower but for some reason seated entirely looser relative to Palma at 47.1.

Palma loads required incremental case twist seating similar to lug nut tightening to ensure straightness and bullet nose condition perfection. Standard loads received that too but there was simply no resistance for some reason and they crossed the target some 45 FPS slower. The striking accuracy and velocity differential was notable. The .1 grain difference was to account for a much larger BR2 primer. The Palma case is apparently smaller internally, - thicker walled - and tighter necked.

All the brass was new, and none of it displayed high pressure signs.

Once sorted out with the set up, the second Palma brass relay showed me very good accuracy with F-Open type holds. But 50 rounds to follow with myself and PJ shooting Standard Lapua brass weren’t accurate. I wish PJ could have shot the better load.



​

 

[Trashy]

I want to see a 250 loaded into a 300blk case for reasons. would the 300blk be able to get 1k fps out of those? Not trying to thread Jack.

 

[Ray123]

I’m going to say no to a 1-9 twist for the 250 ATIP. I’m running a 1-9 twist and have shot the 225 ELDM, 230SMK and the 230 ATIP’s and all have shot excellent. Only shot the ATIP to 430 yards so far. I’m running them out of a 300PRC at 2900fps.

The 250 ATIP per Hornady need a 1-8.5 twist minimum. According to my twist calc’s I’d go with a 1-8.25 or even a 1-8 twist.

A 308win and at lower velocities and now throw in temperature/environment conditions being a variable.....a 9 twist won’t be enough in my opinion.

Later, Frank
Bartlein Barrels

Just ordered a .308 1-8 twist Bartlein barrel 31" for a 300 RUM project...but I have a .308 Win reamer, could waste some time chambering to a long action Rem 700 at 3.410" C.O.A.L. with a throat reamer in .308 Win with 250 grain A-Tip, which would leave a lot of room for powder, and feed from the magazine...just for fun and to see the reality of it. I ran the 250 A- Tip at 2986 fps with the 300 RUM and a 26" barrel, but they are not stable, with a 1-10 twist..

 

[Ray123]

Just ordered a .308 1-8 twist Bartlein barrel 31" for a 300 RUM project...but I have a .308 Win reamer, could waste some time chambering to a long action Rem 700 at 3.410" C.O.A.L. with a throat reamer in .308 Win with 250 grain A-Tip, which would leave a lot of room for powder, and feed from the magazine...just for fun and to see the reality of it. I ran the 250 A- Tip at 2986 fps with the 300 RUM and a 26" barrel, but they are not stable, with a 1-10 twist..

Update: So I actually chambered the long action and 30" finish length barrel to .308 Win. After some testing with the new .715 BC 200 grain bullet, I feel I may stop here...ran the usual powders with expected velocities.. But one combination was giving me 2860 fps with good accuracy with a .715 BC 200 gr. Sierra MK...super ballistics for a .308 in case anyone is interested.

 

[APGE]

Update: So I actually chambered the long action and 30" finish length barrel to .308 Win. After some testing with the new .715 BC 200 grain bullet, I feel I may stop here...ran the usual powders with expected velocities.. But one combination was giving me 2860 fps with good accuracy with a .715 BC 200 gr. Sierra MK...super ballistics for a .308 in case anyone is interested.

2860 for a 200 is blisteringly fast. What's the powder charge?

 

[Ray123]

I want to see a 250 loaded into a 300blk case for reasons. would the 300blk be able to get 1k fps out of those? Not trying to thread Jack.

250 A Tip will run a little over 1300 fps in a 16" barrel. Use a 300 blk specific mag, milled (cut )out so you can feed 2.350" cartridges. My accuracy was not that great, But I had other projects to do...need to try other powders. Sierra Bullets Will have data on the new 230 gr and old 240 gr MK on line for starting loads.

 

[Ray123]

2860 for a 200 is blisteringly fast. What's the powder charge?

I use Lapua Palma brass, Br4 primer, 50.8 grains of power pro 2000mr loaded to 3.175".COAL.. With a 30 " Barrel in a long trued 700 action. And I have a piloted throating reamer to keep extending the throat to get the COAL I want. I Was gonna throat 3.410" for the 250 A Tip, but this is a good load and a longer throat will ruin it for the 200's. You must have the long throat (cartridge OAL) in order to even try this... as it would be very dangerous (explosive) with a normal length 308 load.

 

[coolbox]

Any final word on the experiment?
Did the 250gr A-TIPs do any good in 308?

 

[Kurz]

From Berger:



The above is based on the original supposition of 2400fps. As Frank states the better bet is either the 8.25" or the 8.0" twist.

I have a slightly shorter barrel in an 1:8" twist which I will re-chamber from an unused .300 Blackout to the .308 Win. for some fun testing.

 

[JFrank]

I wonder if that big ol bullet ever made it to the 1k line??

 

[paulT]

None of this is a suggestion, kids. I use CCI 41 primers for experiments like this. 47.0 grains of RE 17 exhibited zero bolt lift resistance. The primer looked exactly how I anticipated it would, - fully utilized . (I’ve used 50 grains for 230’s). The shot was into sand solely to test pressure. Based on recoil, I don’t imagine this is a very fast load, but I’ll prep some at this level for target testing and follow up.

What was velocity with your re17 47grain Load.

 

[davidjoe]

What was velocity with your re17 47grain Load.

A while after that post I switched to 4350 to test. I actually favored 48 grains of 4350 in fire formed brass, compressed, looking for 2,430 or so. But to answer your question 17 was much faster, a specific number here would just be a rabbit trail though. We know that 17 can push open bullets faster as well but guys haven’t found it conducive to small group size.

 

[Mr.Knowit all]

I think you will need faster than a 9 twist if it is for a .308 win

You will.

 

[paulT]

A while after that post I switched to 4350 to test. I actually favored 48 grains of 4350 in fire formed brass, compressed, looking for 2,430 or so. But to answer your question 17 was much faster, a specific number here would just be a rabbit trail though. We know that 17 can push open bullets faster as well but guys haven’t found it conducive to small group size.

Might yield increased velocity with vit N150 Verses H4350
Accuracy and temp stability should 9also be on par with with H4350
However i suspect this Long Bullet at Long Ranges 900-1200 Yards will give much increased Vertical verses shorter 185g-200g Bergers in Switching Head and tail winds even when compensating for L to R Angle changes.

 

[Evan]

Yesterday the 250’s registered 1,540 FPS at 1,000. The SD’s at the target were in the 8’s in each of 4 test relays, 2 with Palma brass and 2 with standard. The standard brass accuracy lagged about 10 points behind the Palma. My lower score with standard was confirmed by PJ who shot the 4th relay. Standard was loaded only .1 grains lower but for some reason seated entirely looser relative to Palma at 47.1.​

​

Palma loads required incremental case twist seating similar to lug nut tightening to ensure straightness and bullet nose condition perfection. Standard loads received that too but there was simply no resistance for some reason and they crossed the target some 45 FPS slower. The striking accuracy and velocity differential was notable. The .1 grain difference was to account for a much larger BR2 primer. The Palma case is apparently smaller internally, - thicker walled - and tighter necked.​

​

All the brass was new, and none of it displayed high pressure signs.​

​

Once sorted out with the set up, the second Palma brass relay showed me very good accuracy with F-Open type holds. But 50 rounds to follow with myself and PJ shooting Standard Lapua brass weren’t accurate. I wish PJ could have shot the better load.​

Any news on how the 250s are doing in the 308? I'm interested to see how tightly you can control your vertical with that setup.

 

[davidjoe]

Any news on how the 250s are doing in the 308? I'm interested to see how tightly you can control your vertical with that setup.

I’ve been wanting to give these bullets the benefit of a fresh barrel, but it has to be an 8 twist. About 12 weeks ago, I had thought that I had made progress on 2 existing Walther blanks, but the email chain went quiet from their end. There has been literally no 8 twist 30 cal in inventory in the country over this period. A couple customs may be my only option but I have not relished the idea of how long such an order that cannot be combined at the production level, with anyone else’s, would take.

I’ve bore scoped my current gun and I’m very happy with the condition over it’s rounds fired, but two things come to mind on it, the barrel is uniquely fluted and the entire barreled action is cerakotaed FDE to match a custom stock, such that I’d rather shelf it as a unit and use a brand new more mundane and TR-prototypical set up, and secondly, if I don’t test these bullets with a fresh barrel, I could be doing them a disservice even if the results were good, had the potential actually been “great.”

My gut feeling with the tests I have have started is that the 250 will shoot as accurately at 1,000, with the same wind calls, as if that shooter had dropped a .284 barreled action in that same TR set up, with stout wind loads, in other words more horsepower than 180’s at something like 2,720. This is perhaps an unfamiliar comparison, but wind drift like 195’s in a .284.

 

[adam]

There has been literally no 8 twist 30 cal in inventory in the country over this period.

Looks like bugholes has some 8tw 308 barrels in stock:

Bartlein 30 cal 8 twist SS Heavy Varmint 31''

www.bugholes.com

Bartlein 30 cal 8 twist SS Heavy Palma 31''

www.bugholes.com

FWIW I used to shoot a 7mm wildcat based on the wssm case and shot 195 bergers at about 2450. Most accurate gun I've ever had. The excess drop was inconvenient for PRS, but I still placed well in matches with it. From my experience, shooting heavy bullets with low velocity and a long freebore is not only viable, but produces excellent results.

 

[Culater]

I want to see a 250 loaded into a 300blk case for reasons. would the 300blk be able to get 1k fps out of those? Not trying to thread Jack.

I've done the 225 EDL to 800 with my 300 blk. It was a fun experience. It was very accurate at 600. They where all subsonic loads. You need a fast twist like a 1-6 or faster.