308 - 185 Juggernaut question

[kelbro]

How will the 185 Juggernaut carry 1000yds starting off at 2530fps out of a 308? Found a really good H4895 load. Curious if I should try for the next node up or just go with this one and make my brass last.

At 39.8gr, I'm about .7gr under Berger's listed max.

2.787 COAL about .010 off the lands. Lapua brass.

 

[XTR]

According to JBM you stay super sonic all the way to 1000 yds at 900 feet ASL.

That said, if you are competing in F class most purpose built F class guns with 30" tubes are running them above 2700FPS. (Some are way over that #) The difference is at 2530 you have 8.1" of drift per MPH of full value wind, and someone pushing them at 2700 has 7.3 inches.

If you both miss the wind by 2 MPH you are in the 7 ring and he is in the 8.

 

[Steve Blair]

You're barely there at 1000. QuickTarget shows 1240 at 1000 for a 2530 muzzle velocity. That is at sea level. At higher altitude, it should be better. Try shooting a match with the load. That will tell you pretty quick.

 

[mao0720]

Im near sea level and my ballistic calculator says 1278 FPS at 1000yds. Mach 1 at sea level is about 1126 fps so you are gonna be in that transonic range. Youre probably gonna want more speed to stay above the magic Mach 1.2.

 

[kelbro]

Thanks. I was afraid of that I will try for the next node and will also try a couple more powders.

 

[aj300mag]

2.787 COAL about .010 off the lands. Lapua brass.

Thinkin that's going to be an issue for you. More freebore would work to your benefit.

 

[XTR]

Yea, that's a short throat. I was able to shoot them well last yr with a short throat but I used WW brass (more volume) and I got into pressure problems once with a Varget load that is pretty standard for most F class shooters.

 

[Bob3700]

In 30 inch bbls. check the difference in drift between the 185 below 2700 fps and a 155 Palma (2156) at 2950.

Bob

 

[bricktop]

I think the whole purpose of the juggernaut was stability and accuracy through the transonic region. Could ask Bryan Litz or some people who've tried it how well it does this though. That said, I'm sure it doesn't help it at all going through.

 

[Johnboy]

The 185gn Juggernaut was made to stay stable like the 175gn OTM that Bryan made.So you should be OK with the Fps you are already running,thats if your not wanting to chase the higher node.

 

[wolfman]

Kelbro- you should have no problem finding a higher node with H4895. My last barrel had pretty short throat, and I was still able to get the 185 to 2750 with H4895 in Lapua cases. That was a pretty warm load, but , I expect you could get 2700 without much strain.

 

[aj300mag]

The 185gn Juggernaut was made to stay stable like the 175gn OTM that Bryan made.So you should be OK with the Fps you are already running,thats if your not wanting to chase the higher node.

That would be contrary to the idea of shooting the 185s. Bryan is an advocate of pushing them hard (2800+) to gain the wind drift advantage...

 

[XTR]

Says right on the box that they are designed to remain stable when they go transonic to extend the effective range of the 300WM. That said, I have pushed mine over 2700 since I started shooting them.

 

[Turbulent Turtle]

Remaining stable going transonic is not the same as remaining on the exact trajectory.

Also, the Hodgdon website shows a max of 42.5 for H4985 and 180gr bullets. So I think you're shortchanging yourself at 39.8gr.

 

[ARIZONA_F_CLASS]

There is a 2,850 node for the 185's from what I have heard at the Berger SWLR Nationals.

 

[kelbro]

I thought the throat must be a little short when looking at Berger's OAL. This is a Shilen Match barrel.

I will shoot it as-is and will also try to bump it up and see what happens. So far the H4895 is looking better than the IMR4064. Varget is next on the agenda.