7mm Ultra Loads?

[Hicks]

Long time lurker, first time poster...

I've got a Remington 700 CDL in 7mm Ultra that I've just completed the pillar bedding on. I'm a bit partial to Sierra, and I talked to Sierra about the fact that there is NO data in their manual for this round. A nice "engineer" told me that the reason stems from brass that's too hard (from Remington) and they did not want to get into annealing in the manual. After reading and reading and reading some more (and using a ballistics program) I'm convinced of the superiority of a heavy for caliber bullet. I'm looking at 175gr only. Does anybody have any experience with this caliber? Loads?

The experience of this site is much appreciated.

Hicks

 

[sambo3006]

The only bullet I have shot in mine so far is the 150 gr Ballistic Tip. 90 gr of IMR 7828SSC with a Fed 215GM primer will comfortably launch it at 3375 fps out of my factory 26" 700. Groups run around .5" or a little less at 100 yds. I know this is a little lighter bullet than what you are looking at. You might also look at the 160 gr Accubond in addition to the Sierra 175. Best of luck with your rifle.

 

[royinidaho]

Hicks,

Remington brass too hard? Nah, I don't think so!

Google around, you'll find something.

Try Accurate Arms, they have loads but for some reason, if I recall correctly, don't list 8700 for that cartridge. I'm a bit fuzzy on this one though.

 

[Budman]

Hicks take a look at hodgdon's web site and you will find data for the 175 grain. I have 3 set up using the 160 accubond with retumbo and played with the 175 Seirra and US869. They did shot out of a 9.5 twist ok but ended up being to long for the current mag. length so I went back to the 160 accubond. Recoil grows also with the 175 and a brake really is needed. Dave

 

[dirtball]

Long time lurker, first time poster...

I've got a Remington 700 CDL in 7mm Ultra that I've just completed the pillar bedding on. I'm a bit partial to Sierra, and I talked to Sierra about the fact that there is NO data in their manual for this round. A nice "engineer" told me that the reason stems from brass that's too hard (from Remington) and they did not want to get into annealing in the manual. After reading and reading and reading some more (and using a ballistics program) I'm convinced of the superiority of a heavy for caliber bullet. I'm looking at 175gr only. Does anybody have any experience with this caliber? Loads?

The experience of this site is much appreciated.

Hicks

Here is a Link BUT START LOW and work up to these loads

7mm Remington Ultra Magnum @ www.reloadersnest.com

DB

 

[Hicks]

Hicks take a look at hodgdon's web site and you will find data for the 175 grain. I have 3 set up using the 160 accubond with retumbo and played with the 175 Seirra and US869. They did shot out of a 9.5 twist ok but ended up being to long for the current mag. length so I went back to the 160 accubond. Recoil grows also with the 175 and a brake really is needed. Dave

Thanks for all the info guys! Budman, just currious, what velocities are you getting with the 160grs?

 

[Hicks]

Hicks,

Remington brass too hard? Nah, I don't think so!

Google around, you'll find something.

Try Accurate Arms, they have loads but for some reason, if I recall correctly, don't list 8700 for that cartridge. I'm a bit fuzzy on this one though.

Ok, so I should not worry about the brass? Well, that makes my weekend a little less complicated...

 

[Hicks]

The only bullet I have shot in mine so far is the 150 gr Ballistic Tip. 90 gr of IMR 7828SSC with a Fed 215GM primer will comfortably launch it at 3375 fps out of my factory 26" 700. Groups run around .5" or a little less at 100 yds. I know this is a little lighter bullet than what you are looking at. You might also look at the 160 gr Accubond in addition to the Sierra 175. Best of luck with your rifle.

Groups that average .5" would be fine with me. I may try those ballistic tips. On another note, I'm a little unhappy with the fact that my dad, who has a .300 ultra, can get 3200+ fps with a 180 gr and I can't break 3200 with a 175. It seems to me that, with the same case capacity I should be getting at least what a 300 gets with a lighter bullet. I've never chronographed this, just what I've read in manuals. Any ideas why this might be? Any idea why there is little published data from the bullet/powder manufacturers?

 

[Budman]

Hick's with the 160 and factory barrels I am getting 3250 with no pressure signs. The 175's shot the best out of my gun at 3150. These loads are all worked up during the summer. Retumbo hasn't veried more then 20 fps with a 50 degree change and the US869 varied 50 fps. The best powder I have used so far has been H-50BMG with only a 10 fps change over an 80 degree change. I hope someone else can explain the reason the 175 grain in a 7 won't beat a 200 in a 30. From mine use they do but I settle with accuracy verses speed. Dave

 

[Hicks]

I hope someone else can explain the reason the 175 grain in a 7 won't beat a 200 in a 30. From mine use they do but I settle with accuracy verses speed. Dave

Yeah, it's one of life's great mysteries. Very disappointing.

 

[41mag]

I hope someone else can explain the reason the 175 grain in a 7 won't beat a 200 in a 30.

Well not that I am an expert on it, but I would say expansion ratio & bearing surface.

Depending on the bearing surface you will hit higher pressure signs in the smaller diameter longer bullet than you will in the fatter bullet with less surface.

Also even though not that much actual difference in bore size the .284 is still smaller than the .308 and when getting into top ressure loads this will make a difference in burn rates and pressure peaks over the distance of the entire barrel length.

Just my view of it.

 

[davewilson]

the reason for higher speeds with larger diameter bullets is more surface area being pushed on. there was quite a debate on this a while ago, less bearing surface, faster burning powders and about 16 other things all come into play. just remember a larger dia bullet will usually be shot at a faster speed all things being equal.

i had a 7rum with a 30" barrel and shot the 180 Bergers around 3250 with 99 gr of 872. i know Retumbo would give more velocity.

 

[bchunter2]

I can help you with 180 grain Berger loads if you are interested for the 7MM Ultra Mag? I shoot 168 g Bergers in my 7MM Ultra Mag. 1/2 MOA at 100 yds. Velocity 3112 ft/sec.

 

[chickm1]

Hicks, One of the guys at Sierra told me that they would never have loads listed for the 7mm RUM, after they had a bad accident in the testing lab. He told me the 7mm RUM was the ultimate overbore, and once you reach a certain point in loading, the pressure starts to increase dramatically, and that is what caused the accident during testing. He would not tell me the specifics of the accident or anything else, except that if I wanted the ultimate 7mm, to rebarrel to 7mm STW.