Proper Headspace

[Stats Shooter]

Been some discussion on if the magnum really headspace on the belt

From talking to some gunsmiths, and my own experience, the answer is yes AND no. A factory loaded SAAMI spec round in my old chamber grew about .015 in length at the shoulder....And almost that amount if I FL sized the case all the way down until my base touched the die.

So when I neck sized Wich didn't really impact the shoulder, then it probably headspaced off the shoulder, and or at least it could have.But if the shoulder is .015 from the chamber max shoulder length, then it's headspaceing off the belt.

So essentially, if you are shooting factory ammo, or FL sizing back to SAAMI, then you are on the belt....If not, probably the shoulder.

My OP on this thread though arose because I'm doing my first Savage barrel swap with barrel nut and wanted to know how tight to make the bolt close on the go gauge.

 

[reynolds357]

In new brass and factory loads, the belted magnum headspaces off the belt. In reloads, it all depends on how it was sized.

 

[RC20]

Yep to both.

As for the Savage, set it a bit loose on a go gauge.

that is someplace between where the bolt will start to close but not fully.

At that point a Factory round (or new brass) should chamber with no effort.

Your first shot will fire form it. As tight as you can get it will have minim brass stretch on that first shot.

My take is rather than do the neck size thing that will need to be FL sooner or latter anyway, is do a minimum shoulder bump back.

 

[Stats Shooter]

One comment....The factory barrel nut was on pretty darn snug.....Too snug. Specs say 70 ft lbs....that nut was A lot more than 70 ft lbs....I had to use my breaker bar on the barrel nut wrench with the barrel in a vice.

 

[reynolds357]

The nut being on too tight is the norm, not the exception. One thing I have learned in machinery maintenance is that it often takes a lot more torque to break a bolt than you put on it to set it. I pulled a gear box a while back that I had installed a few years earlier. I torqued the main bolts down to 90. When I was breaking them, I could not break them with a breaker bar, I had to get the 1" drive impact. (app 300 ft lbs torque) They were not rusted. Go figure.

 

[RC20]

I have done 3 that were factory so far.

Two were easy, one was hard.

I am not sure hard is the norm.

From the Savage nuts it seems to be maybe 1 in 8 plus or minus.

On the other hand I have a bolt screw I have yet to break loose!

 

[Stats Shooter]

On the other hand I have a bolt screw I have yet to break loose!

If you are talking about the screw in the back of the bolt, I have replaced two bolt handles and had to remove that screw. Both were stiff. What I found that helped ALOT was filling a small tuppeware or glass container with WD40 or some other kind of brake-free type liquid and let the bolt screw end soak in it for a day. then i clamped a set of vice-grips on a big fat screw driver for leverage and with the bolt clamped to my bench i got the screws to turn.

You may already know this, but i will add that you need to put that screw back in VERY tight...if not it can come loose. I used some plumbers tape to keep from having to torque it back in as tight as it was from the factory but, unlike barrel nuts, that screw must be put back on about as tight as it was when you removed it.

 

[Jim Watson]

I saw a picture of the Savage factory barrel installer at work.
He had a looong cheater handle on that nut wrench. Of course he was doing it all day and the long lever arm saves fatigue, but he was still pulling on it hard.

 

[taylorce1]

Easiest way to remove the hex bolt from the rear of a Savage bolt. This is on Savage Shooters Tech page.

First off, as its been said here, the easiest way to remove a stubborn BAS is to insert the 1/4" allen wrench as shown below. Then on a carpeted surface or rug, apply pressure (as indicated by the orange arrow) downward with your foot. I recommend wearing shoes when you step down. Do not be surprised if you hear a "crack" sound when the BAS breaks loose, and in rare cases you my have to bounce or stomp on it to get it to break free.

 

[Stats Shooter]

Easiest way to remove the hex bolt from the rear of a Savage bolt. This is on Savage Shooters Tech page

That's all well and good.... Except that the screw on both my bolts takes a flathead screwdriver.

 

[reynolds357]

Heat is your friend. Just do not change the temper of the steel too much.

 

[taylorce1]

That's all well and good.... Except that the screw on both my bolts takes a flathead screwdriver.

RC20 didn't state what kind of screw he has, and I was posting it more or less for his benefit. On the bolt screw like yours I just use an impact driver. One good whack with a dead blow and it's loose, can do the same with a hex head screw if you own an impact driver.

 

[Stats Shooter]

Here's another question along the lines of Belted mag headspace.... Would a tighter chamber help reduce the potential bulge just below the belt? I really have never had a problem with my belted magnums bulging or separated case heads, the necks crack when my brass is spent.

But wouldn't a SAAMI minimum chamber reduce the chances for bulging? As stated before, the difference between SAAMI min and max in a .300 win mag is 0.008. The difference between my go and No-go is 0.004....But it's still "safe" at say 0.007 Which would not chamber a field gauge but leaves more of the case unsupported right?

I know if you are shooting factory ammo always it doesn't matter (provided it's within SAAMI), but as a handloader, wouldn't a tight chamber help prolong brass life?

I am aware of the collet die, but that squeezes the brass back into shape, it doesn't fix the spot that has been weakened by stretching and squeezed back (work hardened).

 

[RC20]

First you have to hope the slot does not beat out if you use an impact wrench.

Not easy.

Also bolt has to be seriously secured (VICE) any give and the impact is absorbed

I would go with heat (and a vice)


I put mine on a towel and use a rubber hammer per the above setup.

In this case I need a wood piece over the wrench and a 5 lb hammer from the looks of it.

It do not think stepping on this one will do it (I am carefully with sudden jars to my back!)

 

[RC20]

Mississippi:

Any stretch only occurs on the first firing. Its fine to set the head space up as short as you can but not a huge deal.

Your split necks are a result of neck hardening, aka you could extend with annealing.

If you are not breaking cases off at the base then you are doing it right. Minimum shoulder setback is the key.

Just set the headspace to where the bolt starts to close on the go gauge, but not fully.

Cross check that factory ammo fits.

Then go shoot.

 

[taylorce1]

First you have to hope the slot does not beat out if you use an impact wrench.

Not easy.

Also bolt has to be seriously secured (VICE) any give and the impact is absorbed

I would go with heat (and a vice)

I didn't say impact wrench, I said "impact driver" there is a difference. An impact driver is made to be struck with a hammer and it barely rotates the stuck bolt/screw at all. Once you strike a good solid blow with a 1-2lb hammer the bolt assembly screw (BAS) like what's on the Savage rifle will be easy to remove.

Yes it's best to secure the bolt into a vise with "no-mar" vise blocks. I'm able to use all my gunsmith screwdriver bits in my impact driver, so it works just fine on the older slotted Savage BAS without screwing up the slot. When you put it back together a little dab of blue Loctite will keep you from having to torque the BAS screw as tight. It is all pretty easy to do.