Home Forums Hunting & Shooting Gunsmithing Chambering question

I've got a custom 7mmRemExp.
I finally got around to working up a load. I'm loading 140gr BalTip.
Got my length touching the rifling like I always do, loaded the 1st shell .015" off that. It was over .2" longer than a factory shell. Plus it wouldn't even come close to fitting in the blind mag well.

Plan B load to fit the mag well. No biggie. Ran into it several times over the years.

The twist is 1:9
Was it chambered for heavier bullets?
What's the purpose of cutting a longer than the well chamber?

I believe I'll be able to make it shoot without any issues. It did solid 1" @ 100yds with factory Vor-tx ammo.

Thanks for any help with my pondering.

R.D.

Most reamers are made to SAMMI specs

It's funny you call it a 7mm Rem. Express. The 7mm Rem. Express was reintroduced in the 80's as the 280.
I bought one then and shot it for 15+ years.
My O.A.L with 140,s was just under 3.3 with a saami chamber so I doudt you have a saami throat with the reamer used.

The rifle was built in mid 1982.

My length touching the rifling is 3.565".
My final was 3.340" to fit in the mag well.

I guess my question should be: why the long throat? Fired brass appears to be spec.

R.D.

I wonder if the reason for the longer throat isn’t erosion from being shot a good deal?

If I truly had a need to load longer than the magazine, I'd be fine running a unit in single shot mode. Not an issue at all with push feeds.

Update:

It shot like crap, best of 4 increments of R15 was 1 3/4" 5 shot group. Case volume was about 70%.
I'm gonna switch powders to R19. Hopefully get my volume up.

Measuring and pondering. I believe it was cut for 175gr plus a bit of freebore. Loaded to the rifling, 1 shell will fit in the bottom. Under the lips but not into the box yet.

Either load to rifling and have a 2 shot or switch powders and carry more in the bottom.

R.D.

I'm wondering if somebody ran a throater in it at some point.

You might try IMR4350.

My 280 shoots 53 grains IMR4350 and 162 grain Hornady Interlock SPBT's .2 MOA - 5 shot groups. It also shoots IMR4350 and 150 grain Nosler Partitions into less than .5 MOA. I don't shoot my 7mm Express 700 much due to collector value.

As far as the long throat, It is not hard to set the barrel back and re-chamber. Have you looked at the barrel with a bore scope? If it's eroded, maybe time to re-barrel.

I run into that quite often where the mag box is short and the throat is way out there.I have to give Remington some credit here.They usually have a generous mag box length.You might try a longer bullet.They seem to shoot better in the rifles I have with those problems.Mono metal and Accubonds also seem to like a little jump too.

Hunting down a scope now.
But from talking with several people, measuring, and pondering, I believe throat erosion is the culprit.
Looks like a rebarrel.

R.D.

He's got a pre-64.....i.e. CRF...

Teslong Borescope works great especially if you have an android smart phone. At less than $60.00 delivered on Amazon you can't beat it. I have had several Hawkeye Borescopes and they work excellent. But at almost $1000 for one really hurts the budget and I was really cautious how I used them, because I was afraid of the mirror getting damaged. The Teslong is ridiculously cheap I use it all the time. Really get a good look at a chamber, throat, and rifling. Regards MP

Thanks MP
I'll take a look at them.

Thanks,
R.D.

I thought the OP had a Remington rifle in 7mm express built in 1982. No CRF in a Remington.

You also have to consider the ogive of the bullet you are using.

Well what did you find out? I am betting the barrel is toast or some one cut a new throat. But the poor accuracy may indicate a bad barrel.

Me I like any excuse to get a new barrel and would probably go 280 AI unless I already had the 280 dies.

Nothing yet.
I work a full-time job in a custom commercial glass shop plus run a small engine business on the side. Been way too slammed to get it to a bore scope. But I did load up a loads to try seated out. I'd just have to shoot it as a 2 shot.
We'll see.

R.D.