Home Forums Hunting & Shooting Gunsmithing What is the normal barrel life for a Remington 7mm Mag Barrel?

My favorite rifle in the stable in a stainless 700 in 7mm Rem Mag. After a little bit of work it would touch three bullets in nice cluster at 100 yards. I confess to not keeping very good records on the number of rounds down range, but i know it's in the hundreds. Probably over 500 but less than 800. Now it seems the old girl struggles to group as well as she used too. Still under an inch, but less than what it used to be. Is it time to buy another pac-nor?

RD

If you continue to shoot a 7RM (or any rifle for that matter) after the barrel heats up then barrel life is greatly diminished. One could easily burn up a 7RM barrel within 500rds if the barrel was not allowed to cool down sufficently during shooting sessions. This is not saying you have done this either.

You might try a good barrel cleaning and then shoot her, maybe she's just excessively fouled. If this did not work, then try different seating depths in your loads as maybe the throat has some wear.

I've never shot out a 7RM barrel because I've never owned the same one long enough to do it nor do I believe in cooking the barrel. I have heard of shooters pushing 1500+rds thru the 7RM before giving up the ship.

MtnHtr

The first centerfire rifle I ever owned was a Rem 700 BDL in 7 m/m Rem/Mag. I used it on Deer,Coyotes,Groundhogs,Crows, you name it. I hunted with it for 9 years while also doing a good bit of paper punching and load development for various bullets. When I finally sold it,it still would put 3 shots well under an inch @ 100yds.

I have no idea how many rounds I squirted down the bore but if it was worn out I didn't know it.

I'm guessing a serious bore cleaning with Rem Bore Clean and CR-10 would solve any accuracy issues you have...

I blew the thoat out of a SS Sendero in 400 rounds a few years ago. I would shoot five in a row, then let it cool completely, then do it again. I was thoroughly and properly cleaning the barrel. Group sizes doubled and velocities fell off. I got rid of the rifle, and ever since then I have been very concerned about barrel life. I stay away from highly over bore chamberings, and I do not shoot with the barrel more than lukewarm to the touch on overbore chamberings.



I understand the problem with the 7mm Rem mag is not so much it's case capacity, but it's short throat and not steep enough shoulder allowing hot gasses and powder to sandblast the throat.

I cooked a new Pac-Nor 22-250 on one prairie dog shoot with only 250 rounds. I thought I was being good and when the barrel would get hot to the touch, I'd swap for another rifle. Apparently that wasn't good enough. I was careful then, but I've been extra careful since.



As others have said, many times deterioration in accuracy is brought about by a badly copper fouled bore. A gunsmith friend recently had a 257 Ackley returned to him as its accuracy had detriorated drastically. The targets he keeps indicated the gun shot three quarter inch groups when it was built. The guy couldn't get 3 rounds on paper at 50 yards after 6 years and about 600 rounds. He cleaned regularly, he said. Borescoping the barrel showed nothing but solid copper throughout the bore. Neither Sweet's, CR10 or J-B could touch it. I have a Foul Out and he called me to borrow it. I offered to do it. Took 5 solid days of the Foul Out changing the electolyte every 6-8 hours to even get where you could see steel, and quite a bit of elbow grease using J-B to get it copper free. When it was done it again shot as when new. The guy just didn't know how to clean the barrel and get the copper out.



It's possible that may be a problem. Without a borescope it's difficult to know you have removed all the copper. As Blaine has said, there may be some throat errosion. You might have a friend with a borescope, or a gunsmith, look at the bore and throat. It could tell you much.



. . .and, PS, you should be able to get 3-4000 rounds out of yours before accuracy deteriorates, if it's cleaned and not overheated.

I have a 300 Win mag that had a similar story. I bought it in 1982 and have put a bunch of rounds through it. What I learned is that it fouls pretty easily. After about 20 rounds or so, the groups start opening up.

This is one SUCKS that I have that probably could use a new barrel. Not because it won't shoot, but because it fouls something terrible. I have to clean the he!! out of it to get the copper out.

But if I do, she shoots as good as it always has.

Tony.

I feel that your 7 mag still has some life left in it. A good cleaning as already mentioned would certainly help. Strong copper solvents and maybe even JB.

Don't overlook the crown. I have had a few rifles over the years loose their accuracy. Was amazed what recrowning did to bring it back. Get a good magnification glass and look it over for the smallest imperfections, doesn't take much.

Don't forget action screws, the possibility of a scope going south, and if the barrel is floated that it still floats. You never mentioned if the rifle was bedded, if it isn't it may help.

You could also try working up a new load. With as many as 800 rounds through it a new load may also help. Afterall some throat erosion has taken place.

The cool part of having you particular rifle is that there are many new rem takeoff barrels in 7 mag. My gunsmith. Harry Lawson Co in Tucson, has around 20 sitting in racks. All are chrome moly. Was at a gunshow in Bozeman a year ago for a gunshow and a gunsmith had several stainless 7 mags. All it takes is adjusting the headspace, if needed and the rifle has a new barrel. Cost is minimal.

I have two mark X rifles with those 7 mag takeoffs and they shoot just fine. Both are 1/4 MOA shooters.

my thoughts.....

I've had a couple barrels that benefitted greatly from a good scrubbing with JB just in front of the chamber. Apparently high capacity cartridges have a way of builing up carbon in that area, and getting it out is a good thing.

Exactly...

CAS - you are sooo right. I just bought a used rifle in .257AI that I knew didn't have over 500 rounds through it that shot very poorly. Scrubbing the barrel left no doubt that there was a bunch of fouling in the first 3-4 inches of barrel. After scrubbing with Sweets and JB's, I took it out to shoot and it shot OK. Back home, the Outer's Foul Out was employed for several hours and there was a a half-penny's worth of copper left in the bore. Now that it is finally clean, it shoots like I expected given the barrel is a Shilen and the gunsmith that installed it is meticulous in his work. Some people just don't clean a barrel. Ward

I was horribly hard on a 7mm BDL that I had for a couple of years. I hunted it hard and killed a lot of critters with it. I LOVED to hunt rock chucks with it at long range. One particular area I liked to hunt had them so thick that you could burn through 75 rounds in about an hour and a half with nothing more than a bruised shoulder and a smile on your face. I would quickly drive to this place after work and have about 1.5 hours of good shooting before the chucks went to bed. It was LOUSY with them. On these trips, I didn't worry about the barrel much, because chucks have a tendancy to cycle and I knew it wouldn't be long before some other guys found the place and shot it out (the chucks weren't smart). I simply hate it when guys think they have to kill everything is sight for bragging rights. I like to go back to the same places over and over and leave some critters for seed. I prefered shooting over 400 yards to insure "less" kills and hone my skills, and because I like long range shooting <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" /> Cooling the barrel was not an option and if I burned up the barrel, so what, take off barrels are cheap. I sold the rifle with just over 1,000 rounds through it. The throat was still intact, but a bit rough. The rifle would still shoot consistent 1/4" groups...yes 1/4" groups! I sold it, because it was getting some surface rust on it from foul weather hunts and I wanted a stainless rifle. Other 7mm's I have owned held up really well. That is why I have a hard time with all the comments about "I burned the throat or barrel out at under 400 rounds." I question their measuring abilities, if they cleaned them to death using poor equipment, if they actually bore scoped them, or if they were just copper fouled. I have abused the heck out of two .22-250's. I have shot them so hot you couldn't see through the scope from the heat waves on numerous occasions. They have thousands of rounds through them. One finally puked at just over 4,000 rounds. The other is still going strong. I would like to know what a "shot out barrel" consists of. A warn throat is NOT a shot out barrel. Throat wear starts at the first pull of the trigger the first time. One .22-250 didn't have ANY lands or grooves for a good inch of barrel, but it still shot fabulous for another 1000 rounds. A 6.5-06 showed serious roughness in the throat at 1,200 rounds, but still shot tidy 1/2" groups. It also got abused on MANY rock chuck hunts. To answer your question about 7mm barrel life. 2,000-3,000 is a good number, if the barrel isn't abused really bad. The one I had would have probably puked at 2,000 if I would have continued on with the extensive shooting I was doing with it. <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" /> Flinch

Flinch,







Don't be an idiot. This is me we are talking about. The measuring was spot on, the rifle was cleaned exactly correctly, the groups did double in size, and the velocity did fall off 150 fps. Could have been bad barrel steel, as this is not uncommon, but all this did happen, whether you question it or not.



Blaine

rdinak,

Look at some other factors besides barrel wear. Some were already mentioned.

The first thing I would do is to clean the barrel. Then check that all of the screws are tight. Next I would change the load to a shorter bullet preferably something like the 140 gr Sierra Pro Hunter. Next I would take it out of the stock and look for something wrong. Finally change the scope.

Then I would do a recrown. I do these myself and they work great. If you mess this up then take it to a smith and have him crown it.

Something is loose or it's fouled. Barrels can last for thousands of shots.

My point exactly!

40 thousands will NOT decrease velocity 150 fps, nor will it open groups up like you state. I have gone through too many barrels with 4 times that amount of hot rounds through them and 10 times the throat erosion to think otherwise. With your "cardboard shims", "bullet runnout issues", "Big Stick, I can't do it your way." and your latest .30-06 fiascos, I really question your reloading and shooting abilities and I am not alone. Anal retentive or not, you sure do some weird stuff and hold it as gospel, since "You are an Airforce pilot." Your "one time" throat erosion scientific test doesn't mean squat, but you sure quote it a lot as gospel. Flinch

Flinch,



I was there with the chonograph, you were not. I did not say my results with my 7 Mag were the norm. I did say they were my results and it changed the way I shoot my rifles. I have been totally honest and open with who I am and what I do, and everyone knows that. I am man enough to post my failures and struggles as well as my succeses.



As such, the way you framed your comments about cardboard shims, the 30-06, Big Stick's way, and being a USAF pilot is misrepresentation, and you well know it.



Over the last little while, you have become one of the most sarcastic and rude posters here. I suggest you go back and read your Bible about what "the Savior" (using your terminology) says about such behavior.



I can defend you no longer, and I did spend some effort defending you to someone here via PM recently. I have given you the benefit of the doubt long enough. I am putting you on ignore. I request you do the same for me. If there is any truth left in you at all, you will honor my request. If you ever decide you can disagree without being disagreable, PM me and we can re-look the "ignore".



Blaine

....YAWN!!! Flinch