Remington 700 Long Range 7mm Remington Magnum issues I

[LRRiflemanSNJ]

I freely admit that I am new to magnum cartridges, but not to shooting or reloading.

I went to the range yesterday to zero my new Remington 700 Long Range in 7mm Remington Magnum, and had too many new experiences. The initial load that I created was well within Sierra's load recommendations. My goal was to develop a functional load for F class 1000 yard matches.

The load:
Bullet: Sierra 168gr MatchKing (.284)
Powder: 65.0 gr IMR7828
Primer: CCI 250 Magnum Large Rifle
Cases: 1 batch using once fired Winchester Western, 1 batch using Barnes, all rounds were once fired, but they were full length resized.

The Barnes brass loads chronographed at 2803 fps, the Winchester brassed loads chronographed at 2780 fps. Sierra's load recommendations would put this combination at about 2930 fps.

The major problem that I experienced was that the majority of the loads using the Winchester brass were difficult to extract after firing. None of the cartridges exhibited signs of excessive pressure, other than the difficult extraction.

I suspect that the lower velocities are due to insufficient crimping, but I am at a loss about the difficult extraction. The bore and chamber were thoroughly cleaned before the range session.

Thank you in advance for any and all constructive advice! gun)

 

[MudRunner2005]

As for the velocities, some barrels are faster than others, and some are slower. It's just the nature of the beast.

As for the chamber, a lot of time factory chambers have rough spots in them, and sometimes you have to polish them out. It's not a difficult thing to do, and I'm sure you can find plenty of write-ups on here on how to go about doing this yourself.

How was accuracy? If accuracy was not the best, and velocity was slow, it could be due to a rough bore. You can also use the Tubbs Final Finish bore lapping bullets to help smooth out the rough factory rifling. I have heard several people who used it say that it gave them more velocity, as well as making it easier to clean.

 

[Outlaw6.0]

The first question that came to mind is: Why are you crimping these loads?


When inspecting your fired brass, are you seeing any deformities/stratches/dents etc?


That could be a key fact to finding out why you're having extraction issues.



t

 

[Wedgy]

I would NOT use the Tubbs FF on a new barrel, just do normal break in. Any marks on the brass exterior ? Velocities will always vary, better too low than too high to start, just bump your way up a little at a time. Some barrels pick up speed after a while.

 

[MudRunner2005]

I would NOT use the Tubbs FF on a new barrel, just do normal break in. Any marks on the brass exterior ? Velocities will always vary, better too low than too high to start, just bump your way up a little at a time. Some barrels pick up speed after a while.

I'm curious as to why not?

I see no real differences in that vs hand-lapping a barrel before break-in... Which makes break-in virtually non-existant. I've had my smith hand-lap 6 factory barrels for me, and break-in took less than 20 shots, and cleanup is super easy. Hand-lapping the bores is what gets all the tooling marks out from the boring and rifling processes. Rifling process, hand-lapping, and air-gauging your tolerances is what separates an aftermarket barrel from a factory barrel.

 

[4xforfun]

"insufficient crimping"???

Any crimping is to much crimping!!!

Do not crimp!!

 

[Wedgy]

Muddrunner, I am a big fan of hand lapping as well but not at 3,000 fps as the Tubbs will do, especially not on a new barrel because you will have no chance to send it back to Remington once you have fire lapped it. Maybe when it is your last option.
I ran FF a couple times including a shot out 308(a lot of rounds to shoot that out) it pushed the throat out enough that my pet load wouldn't fit in the mag with the jump it used to like. I didn't care as it no longer shot anymore, but be aware of what can happen.
Good luck and let us know what happens

 

[mark fox]

You stated the the winchester brass was harder to extract. winchester brass was very soft it will fireform into any minor chamber flaws or tooling scratches. using diffrent brass is no way to work up loads. Case wall thicknes and pocket and flash hole diffrences will produce diffrent ignition and preasure diffrences. Polish your chamber. get matching brass. Turn your necks. Do a full load work up at .007 off lands. Doing anything else is like shooting in the dark.

 

[Canadian Bushman]

How far did you bump headspace back when FL sizing?

 

[MudRunner2005]

Muddrunner, I am a big fan of hand lapping as well but not at 3,000 fps as the Tubbs will do, especially not on a new barrel because you will have no chance to send it back to Remington once you have fire lapped it. Maybe when it is your last option.
I ran FF a couple times including a shot out 308(a lot of rounds to shoot that out) it pushed the throat out enough that my pet load wouldn't fit in the mag with the jump it used to like. I didn't care as it no longer shot anymore, but be aware of what can happen.
Good luck and let us know what happens

Why doesn't he use a reduced load?

 

[LaHunter]

You mention in the original post that this is a new rifle. I would recommend doing a break in for the barrel before you try to develop a load. The way I have gone about breaking in a new rifle / barrel is to buy 2 boxes of factory ammo and I used this as my break in ammo. Buy what ever brand ammo that uses the brass that you intend on using for reloading. I have seen velocities increase as the barrel breaks in. With a factory rifle, it could take 3-4 boxes of ammo. I use IMR 7828 in my 7 mm rem mag also. I use 66.5 grains along with 160 grain Accubonds with about .010" jump and I am getting 3100 fps. I also bump the shoulder back to get .002" headspace clearance. You can't really apply load data from one rifle to another, but just included it for reference.
Also, no crimping.

Good Luck

 

[6.5x300 WBY]

I freely admit that I am new to magnum cartridges, but not to shooting or reloading.

I went to the range yesterday to zero my new Remington 700 Long Range in 7mm Remington Magnum, and had too many new experiences. The initial load that I created was well within Sierra's load recommendations. My goal was to develop a functional load for F class 1000 yard matches.

The load:
Bullet: Sierra 168gr MatchKing (.284)
Powder: 65.0 gr IMR7828
Primer: CCI 250 Magnum Large Rifle
Cases: 1 batch using once fired Winchester Western, 1 batch using Barnes, all rounds were once fired, but they were full length resized.

The Barnes brass loads chronographed at 2803 fps, the Winchester brassed loads chronographed at 2780 fps. Sierra's load recommendations would put this combination at about 2930 fps.

The major problem that I experienced was that the majority of the loads using the Winchester brass were difficult to extract after firing. None of the cartridges exhibited signs of excessive pressure, other than the difficult extraction.

I suspect that the lower velocities are due to insufficient crimping, but I am at a loss about the difficult extraction. The bore and chamber were thoroughly cleaned before the range session.

Thank you in advance for any and all constructive advice! gun)

LRR. Where or what range are you shooting at? Is it central jersey or someother? I am thinking of joining central jersey to be able to poke at 300 yards. Not sure what range 14 at fort dix has to offer but I am looking for a range that has some distance to shoot at.


best of luck I am also sort of in south to sothern NJ. Southern ocean county just north of Atlantic city.


take care

Brian

 

[gillettehunter]

I just picked up a Rem 700 long range in the .300 WM and am having the same issue. Win brass. Brass is tumbled and full length sized. Headspace is between 4 and 5 thousanths. Case doesn't fit well in action with only 2 thousanths. 2 of the 9 pieces of brass already have split necks. Win brass is the roughest I've ever seen. Just not real happy at this point. Broz mentioned to me at this price point QC and overall care is likely lacking. Going to polish the chamber and go from there. Bruce

 

[mark fox]

I just picked up a Rem 700 long range in the .300 WM and am having the same issue. Win brass. Brass is tumbled and full length sized. Headspace is between 4 and 5 thousanths. Case doesn't fit well in action with only 2 thousanths. 2 of the 9 pieces of brass already have split necks. Win brass is the roughest I've ever seen. Just not real happy at this point. Broz mentioned to me at this price point QC and overall care is likely lacking. Going to polish the chamber and go from there. Bruce

is the brass new winchester? if so why would you tumble cases spliting is a sign of work hardened old worn out brass. if it not new brass get new brass problem will be solved 300 wm brass quality is a problem and there is 2 diffrent saami 300 wm chambers on the market in factory guns talk to dave kiff at at pacific tool and gage he will confern my comment. if it has been fired in a diffrent chamber it can be next to impossible to resize to fix problem. get new brass it will fix the problem.