7mm remington ultra mag

[James Gleave]

I was just curious to see if any of you guys use this caliber and what do you think? What are your experiances with trjectory from different bullet weights? Any info on this caliber will be helpful. Thanks.

[308Nut]

162 AMAX trajectories in the 7 RUM are impressive. Equally as impressive is the very short life of the throat and bore. A good ballance between flat shooting and barrel life is the 7 rem mag or the 7mm RSAUM. The 260 rem running 140 Amax bullets or 140 VLD's is also a very good wind bucker as trajectories meen little in the age of rangefinders.

 

GL in what ever you decide.

 

M

[Red Rabbit]

Michael,

What kind of throat life are you hearing about on the 7RUM? A neighbor is very interested in getting one.

 

Doug~RR

[308Nut]

Michael,

What kind of throat life are you hearing about on the 7RUM? A neighbor is very interested in getting one.

 

Doug~RR

 

Depending on how the bore was cut and whether or not it is a factory barrel or custom, I have heard of the throat being chewed up in less than 100 rounds. I have never owned one so I cannot vouch for that. What I can vouch for is the 300 RUM. I had a cut rifled barrel that the throat didnt make it to 70 rounds and a button pulled barrel that made it to around 150. Albiet I was hot-rodding them. I cant imagine the 7mm being any more forgiving.

 

Both settled down after a few hundred rounds but I was limited in the velocity I was able to get due to the added friction of the cooked throats. The 300 RUM is capable of 3350-3400 FPS with 180's in a 28" custom barrel. I was stuck with 3250 with both after the throats cooked.

 

Of course it will depend on how fast shots are fired consecutively and how often it is cleaned and how it is cleaned. Also it is a theory of mine that factory barrels last longer than custom barrels. This MAY be due to custom bores are as perfectly finished as they can be. When it is a perfect finish, it can only go downhill from there. When you have a rougher finish, it smooths out and 'breaks in' offering some added life. Again, this is only a theory.

[jeffro]

From what I have read the 7mmUltra barrels go 600-800 rounds, but as you know there are many factors that are involved in that number. My friend has a 7mm Ultra that has 600 rounds through it, and it still shoots OK. 3/4 MOA, but that was the best he ever got out of it.

[youngbuck]

When I was picking out my "go to gun" I was set on a 7RUM. That is the reason I started to reload. I wanted to be decent at it when i got my 7RUM. Kicked it around a bit and couldnt find any reason not to go 30 cal, my dad already had a 7mag. If you dont shoot it a ton they work great for what i do. I have seen great results from 160 AB outa big 7's; STWs Ultras and WSM. I happen to load 140 AB outa for our 7mag and seen 140AB shot outa 7WSM. They all shoot great.

[LazzInc]

7mm Lazz Firebird is a good bit faster and flatter than the 7mm RUM ,,,,, barrel life is around 900 rounds with a Top-notch Lazz Barrel and Lubed bullets,,,, John@Lazzeroni.com ,,,,,

[James Gleave]

Thanks for all the info.

[Couesdeer]

I like my 7RUM.... Factory 700 Sendero. With moly'd 140 gr Nosler BTs and a heap of Re25, I'm getting 3665 fps. Moly'd 140 gr. Barnes TSX give me 3600 even. (My rifle really likes the ballistic tips...)

Can't comment on barrel life as I'm only approaching 400 rounds through this tube and everything's fine so far.

 

[LazzInc]

What kind of groups do you see at 500 yards with the reloader 25 powder and 140 b-tips ? ,,,

[Couesdeer]

Most of my pre-season shooting consists of blowing up milk jugs filled with water at various distances. However since this year was my first time messing with elevation turrets instead of holdover, I did shoot this group at 495 yards. (Prone off a bipod and a rolled-up towel under the buttstock)

I didn't put a tape measure to it, but I'd reckon its somewhere between 5 and 6 inches....

One of my buddies has abandoned the 140 grain bullets in favor of heavier Berger offerings with a greater BC.... I just have so darn many 140s.....

 

[firstcoueswas80]

My dad has a 7 RUM and we like it. It shoots well, and dropped his coues at 531 a couple years ago with one shot! 140 Accubonds work great

[LazzInc]

couesDeer ,,,,,,

 

a 5 1/2" group at 500 yards is very good ,,,,,, but I think you could get it under 3/3/4" @ 500 by switching to IMR-7828 powder, and federal 215M primer ,,, and seat the ogive of the 140gr b-tip bullet about .010" off the lands ,,,,, "IF" they will still go in the mag box seated like that ,,,,,, otherwise seat them as far out as you can, but still having them fit the mag box ,,,,,

 

then work the load up to about 60 fps SLOWER with the 7828 than you are going now with the reloader25, to further improve accuracy while keeping an eye on pressure ,,,,,, then when you have settled on the FINAL load ,,,, then load up a hundred or so with new brass, then rotate the LOADED cartridge case necks on a concentricity gauge from RCBS to cull the ones with .002" or less run-out from the rest ,,, and use the .002" or less ammo for your long range shots at trophy game animals ,,,,

 

if there was ever a better powder made for the 7mm magnum bore, than IMR-7828, I don't know of it ,,,,,,

 

BTW ,,,,,, I just was at the 550 yard range this morning in my final preparation for Mexico Coues Deer hunting tomorrow ,,,,, first three shot group out of my personal Warbird ,,,,, measured 3 & 5/8 " ,,,,, no wind right at 7:00AM either, so I had a chance to correctly set my scope windage right on at 550, which is also important ,,,,, John@Lazzeroni.com ,,,,

[Couesdeer]

Thank you so much for the information.

I'll give the 7828 a shot..... Already been seating bullets .010 off the lands and using 215Ms. I've never used a concentricity gauge before. I'll look into one...