Long Throat!

[Willys46]

I just have to check, I am reloading my brothers 7RUM. HOLY COW is the throat long. I can't even seat a 168 berger or 160 Accubonds and hit the lands! Even if I could I would need an additonal .5 inch in the mag well to fit.

I have a couple remington 700's but all have custom barrels. This must be waht every one talks about comming form the factor long throats.

Is this the Norm? I would have imagined I could at least hit the lands disreguarding the use of the mag box.

If I seat the bullets to mag lenght I will be close to .5 inches of the lands.

Could this be the reason I am getting carbon down the necks, and high extreme spreads on velocity?

 

[Joel Russo]

Cody,

That's the norm with the factory 7 RUM chamberings. Philny1 had the same problem, he couldn't get anywhere close to the lands with the 168 Berger's. He tried the 160 AB and it shot well. He eventually sold the rifle.
If you are going to single shot it, play with the seating depth until you get it to where it shoots the best. Just be cognizant of how much bullet is actually still in the neck. If you are going to shoot it as a repeater, then you are stuck with the 3.700" oal of the mag box.

 

[J E Custom]

Remingtion has done the same thing that weatherby did along time
ago, add more freebore to get more velocity "Safely" .

After talking to an engineer at Remingtion about this He said "QUOTE"
We had concerns that with the trends of people wanting to seat bullets
near or against the lands pressure would become a safety issue,so
we limit the C,O,A,L with the magazine .

He also stated that if you single load with bullets touching the lands
the loads should be worked up slowly to maximium pressures.( most
reloaders all ready know this).

I encountered a case where a person tried to use factory Weatherby
ammo in a custom 30/378 with no freebore and blew three primers in
the first three shots fired from the box.

So Yes it is on purpose and not a quality issue.

But I have not found this to be an accurace issue if properly headspaced.

P.S. All of the RUM,s are throted deep . I did not ask about the Short action
Ultra Mags (SAUM,s).

I guess With all the lawsuits everyone is running scarded .

J E CUSTOM

 

[Willys46]

Thanks

I can understand limiting people by the size of the mag box, but I was looking at single shooting the thing and the bullet fell ofut of the case before I hit the lands.

O well, it was shooting the accubonds well, I was just going to play with the bergers and no how they want to be in the lands. O well!

Thanks for the response. It's just another reseaon to build a gun and not buy one.

Have a good night guys!

Willys

 

[jwp475]

I don't know about running scared, but I do know that every piece of Steel no matter the grade in not the same strength. 4140 will be manufactured to a minimum and this is the stated strength and not the maximum, with out the Mill Certs the only way to find out the maximum is by destructive testing. Loading loads above SAAMI max is a slippery slope. Getting away with this does not make it safe, safe is removing 100% of the hazards and any loads above SAAMI has not removed 100% of the hazards.

 

[shootinfool]

my brother just had a 7rum built by christiansen arms and his has the same thing. I know he really wanted to shoot the 168 bergers but was unable to get them to even touch the lands just like you said. I know that he is currently shooting accubonds out of it with extreeme accuracy even though they are seated to jump quite a bit before engaging the lands and grooves. I know he contacted the company about it but I cannot recall what the answer was on why they do this sort of thing, even in a custom build.

 

[Ridge Runner]

try the 200 gr wildcats, they're like 1.6" long you should get to the lands with them. and they'll run fine in a 9 twist
RR

 

[J E Custom]

All reamers are ground to SAAMI specifications unless you get custom
reamers made with less freebore.

A gunsmith will allways use SAAMI unless you ask for something special.

But remember if you shorten the freebore you will have to load down and
probably loose velocity(The reason for going to a Big cartrige in the first
place).

Freebore does not prevent a cartrige from being accurate !!!!

J E CUSTOM