7mm 190gr A tip

[jackieschmidt]

Will a 1-9 twist stabilize that 190.

I just bought a 1 1/4 diameter straight Krieger from a fellow member here, and against my shoulder’s complaints, I am going to chamber it in 284. My 284 reamer was designed from the 180 Berger Hybrid, so I think it will be ok.

 

[No i deer]

So are these 190gr A tips proving to be better than the Berger equivalents.
Will we be seeing a swing in power with shooters moving over to the A tips to have the edge in f open..??

 

[rardoin]

Will a 1-9 twist stabilize that 190.......

Berger’s stability calculator suggests a 1:9 would be very marginal for 500 asl, 59F, 2700fps. Maybe if you shot close to home in cooler months. You would be better off with a 1:8.5 or 1:8. You will be fine with the 184 for certain out to 1000 and at altitude.

 

[rardoin]

So are these 190gr A tips proving to be better than the Berger equivalents.
Will we be seeing a swing in power with shooters moving over to the A tips to have the edge in f open..??

Not much reporting On the Hornady 190 A-tips from the Fclass crowd but I hope to be able to report something soon in a 7 saum variant. The boat tail is too far in the boiler room on my .284/.225 freebore to test them. I’ll wait for the new build.

 

[rardoin]

I have been playing with the 190's in a 7 Sherman Short mag. I did an crude seating depth test at 100yds with an arbitrary charge that produced right at 2800fps. I chose 0.035" off light touch based on the results. I did a coarse charge weight test (.5gr increments/ H1000) with 4 shot groups at 965yds to sweep from around low 2600's to 2800 fps. The extreme groups were 3 in/ 1 out, nearly all vertical, and that tightened up in the middle group at 2750fps. I'll run another test with more shots per group with .2gr increments with the 2750fps charge as the center. I've got to wait on good conditions but hopefully I can find a promising charge that proves out over a 20+ shot string. So far it is encouraging.

At 100yds:

At 965yds:

 

[Kratos]

So I guess I’m not going to be able to do much with these and my 0.188" freebore?

 

[davidjoe]

Robin, Sunday I shot A-Tips at the 1,000 yard Bayou from my .284. I was relay 3 and by then it was windy but the vertical discouraged me. I ended up putting it away after match 1 and pulling out my rsaum. The fact that my daughter had shot a 198 with 195’s didn’t help. (Followed by son with a 195).




So for the rsaum I had brought Berger 190’s. This skews the comparison because the rsaum obviously shoots faster.

But I feel like the rsaum wind was at least as significant as in the earlier match. The saum/Berger combination shot a 196 in match 2 and a 198 in match 3. What will be interesting is how the saum shoots A-Tips at 1,000. But it’s good to know the new Bergers work well. I love the 195’s but I’m not risking another saum bullet blowup.

 

[rardoin]

I'm not sure that the .284 case will do this long arse bullet justice David. I hope to fine tune the charge weight at distance soon then maybe be ready to shoot them in the July LRA match at Shreveport. Not the best range to assess vertical though. At this point I'm encouraged enough to order more...not by the thousand though.

By back calculation of the terminal velocity I estimate that you were running the A-tips at 2685fps or so MV. In my really preliminary testing my best groups were in the 2750fps range seated 0.035" OTL. I have not tried to get them over 2800fps yet.

 

[davidjoe]

At their higher cost, I think you are right that the cartridge choice needs to fully exploit that high BC and presumptive uniformity. It wouldn’t make sense to strive to only match existing choices, but pay more to do so. That would point to the magnums. (I have tested a few in a saum, but only at 600, the so-so results made me want to validate-test them in a .284, I’m just going to have to shoot a whole 1000 yard match with them in a saum.)

There was a rotatable bit more to Sunday, while my kids also shot .284’s and put me (relay 3) in third place at the conclusion of match 1, when they too shot in the wind, they didn’t actually do better overall than the A-Tips had.

Royse shot the highest X count of us three with old Sierra 180’s for 2 matches and 195’s for match 3.

It did not escape their attention that I pulled out the bigger gun to pass in match 2 and 3.

 

[rardoin]

Don't be afraid to try big jumps with these David. They shot pretty crappy in my rifle closer to the lands where most seem to run Bergers. They woke up with a bit of jump.

 

[Kratos]

Let me ask this differently. What freebore do people think would be optimal for the 190 A-tips in 7mm SAUM?

 

[davidjoe]

I don’t have seating depth maximized yet, to say. But back a while I found that soft jamming 300 grain .338 A-Tips resulted in large groups. Seems to be the case that all of these bullets do better jumped. The bearing surfaces of 190’s are not unusually long. They have very long noses and boat tails. In 7mm for example, both 180 Scenars and eldms will touch the lands at a given stem setting whereas these will not. Sami spec reamers work without using a throating reamer.

 

[rardoin]

Let me ask this differently. What freebore do people think would be optimal for the 190 A-tips in 7mm SAUM?

My 7 Sherman Short has a fireformed neck of about .31". The bearing surface of the 190 A-tip is .679". I am shooting them with a 0.035" jump and my gunsmith throated it to match a 'dummy load' seated to have the base of the bearing surface about 0.020" above the shoulder junction. The freebore is in the neighborhood of 0.300". My load for the Berger 190 LRH at about 0.040" off the lands has the base of the bearing surface about at, or just over, halfway to the case mouth...a big difference compared to the 190 A-tip. I am just crunching powder at 59.9gr H1000. If I find these bullets are grouping consistently enough to win 1000yd F-class matches then my next barrel will be throated about 0.020" longer than this one. If that is not the case I will drop the A-tip experiment and throat the next barrel .260" so I can shoot the 180-190gr Berger hybrids.

 

[No i deer]

Is the 190gr A tips BC working out..??

 

[rardoin]

Is the 190gr A tips BC working out..??

As best as I can measure by predicted vs observed drop at 965yds, definitely yes. I am using an 8.25 twist barrel.

 

[No i deer]

These A tips could start dominating f class competitions with there big wind saving Bc's

 

[davidjoe]

If guys can keep the groups small, yes. Sierra had some very high BC releases with the 197 and 183 a few years back but I don’t think a lot of shooters saw aggregate scores go up with them.

 

[Kratos]

Thanks for the info. Is the case capacity similar between the Sherman Short and SAUM? Touching the lands by Wheeler’s method, I get the following:

Berger 180: COAL 3.099, BTO 2.364
Berger 190: COAL 3.128, BTO 2.366
A-tip 190: COAL 3.146, BTO 2.345

With the A-tip, the bearing surface is clearly below the neck/shoulder junction (and it’s pretty close with the Bergers).

I may fire a few with a light load (59 gr H1000 or so, I have been using 63 gr for the 180s) but I have ordered a uni-throater kit.

My 7 Sherman Short has a fireformed neck of about .31". The bearing surface of the 190 A-tip is .679". I am shooting them with a 0.035" jump and my gunsmith throated it to match a 'dummy load' seated to have the base of the bearing surface about 0.020" above the shoulder junction. The freebore is in the neighborhood of 0.300". My load for the Berger 190 LRH at about 0.040" off the lands has the base of the bearing surface about at, or just over, halfway to the case mouth...a big difference compared to the 190 A-tip. I am just crunching powder at 59.9gr H1000. If I find these bullets are grouping consistently enough to win 1000yd F-class matches then my next barrel will be throated about 0.020" longer than this one. If that is not the case I will drop the A-tip experiment and throat the next barrel .260" so I can shoot the 180-190gr Berger hybrids.

 

[rardoin]

The capacity is near identical even though the SS body is shorter; the case has less taper, a 40deg shoulder and a longer neck. You would probably need a .330 or longer fb to get the bearing surface within the neck.

 

[MattPeetz]

These A tips could start dominating f class competitions with there big wind saving Bc's

Lolololololol.