Dasher Brass Oversized Issue

[lennyo3034]

I have a new Dasher build and am having trouble when chambering. I'm hoping to get some help.

Barrel is a Shilen Savage prefit, and action is an ARC Nucleus. When I installed the barrel, I tightened the barrel nut with the go gauge in the chamber. Go gage chambers, but is a bit tight to close, as expected. Chamber is a Lapua Dasher chamber.

Trimmed Norma dasher brass is extremely tight to chamber. Tighter than even the go gauge. This is the case for both virgin and fired brass.

Hydroformed Lapua cases from Hunt's chamber without issue for first firing. However after I resize on my Forster die, they once again become difficult to chamber. I find it interesting that the once fired brass will go in without issue, its only after I size the brass where I'm having issues. So far, I don't even know what part of the case is causing issues.

Any suggestions? Obviously the sizing step has something to do with it.

 

[expiper]

it is a common problem with savage bbls that are headspaced too small,,,losen the bbl up a little and then your resize die will be able to size the ctg cases small enuff to fit,,,Roger

 

[Sheldon N]

What you need to do is measure. Get yourself a headspace comparator like the one from hornady and check the dimensions of fired and sized brass at the shoulder.

If fired brass chambers but sized brass doesn’t, then my guess is that you have squeezed the body of the case, pushing the shoulder forward instead of bumping it back. The fact that Norma brass also will not chamber suggests that the headspace is tight, probably because you’ve set headspace tight on the go gauge.

If you confirm, the simplest thing is to back the barrel out a bit so you have a touch more headspace and your current die can bump the shoulder on fired brass.

 

[Liven The Dream]

I went thru the complete Foster Die problem in the Past.. Make a Paper weight .
In my case I spent lots on new dies...$$$$$.
I found out later a Std. RCBS Die worked
I use the $$$$ Bushing Dies less run out.

Good Luck

I all so have a Dasher with the Norma Dasher Brass .050 longer neck. I brought the Reamer works .
Widden Dies..

 

[lennyo3034]

Thanks for the suggestions.

Would switching to a neck sized die help?

 

[Sheldon N]

Nothing wrong with Forster dies, as long as your chamber is a good fit for them. I run them in both Dasher and 6BRA with good results. I also have a Harrels die as well.

Neck sizing die is NOT the solution.

As I said above, unless you are measuring what is going on with your brass you are flying blind.

 

[Sundown]

Had the same problem with my dasher when first built. Tried machining the base of forster Die, it didn't help. Throw away the forster die and get a small base Whidden Die. No problem after that.

 

[Sheldon N]

While many well intentioned folks are pointing to small base dies and sizing at the 0.200 line as the problem, I don’t think that’s the issue here. If virgin Norma brass (which has a SMALLER base diameter than Lapua) won’t chamber, it’s a head space problem not a base diameter problem.

 

[Terry O]

Lenny, listen to what Sheldon is saying. He has provided the answers to your problem.

 

[lennyo3034]

I have the Hornady comparator. Which letter should I be using for the dasher?

 

[Terry O]

I have the Hornady comparator. Which letter should I be using for the dasher?

"B"

 

[lennyo3034]

Thank you. I just took some measurements on the Lapua brass:

Once fired brass was .005" longer than virgin hydroformed brass. (Seems like a lot)

Twice fired brass (resized once on Forster) was .001" longer than once fired.

I didn't have and resized and unfired brass available to test.

So it seems like the headspace is growing when I resize on the Forster.

 

[Terry O]

Thank you. I just took some measurements on the Lapua brass:

Once fired brass was .005" longer than virgin hydroformed brass. (Seems like a lot)

Twice fired brass (resized once on Forster) was .001" longer than once fired.

I didn't have and resized and unfired brass available to test.

So it seems like the headspace is growing when I resize on the Forster.

Your almost home. Now adjust your FL down a bit at a time while measuring each move until your .002 to .003 less than your twice fired size and you should be good to go.

 

[lennyo3034]

Your almost home. Now adjust your FL down a bit at a time while measuring each move until your .002 to .003 less than your twice fired size and you should be good to go.

Just did exactly this. Resized brass is .002 smaller now. And .001" shorter than once fired brass.

Still very tight to chamber. Since it's not headspace, what else could be tight?

 

[expiper]

if they are shorter and smaller ,,,they oughta go !!!....check response #2 and then your resize die will make them go ,,,Roger

 

[steve123]

Maybe this chamber has a tighter neck???

If the body is .002" smaller at the web and the shoulder is bumped back .001" what else could it be?

I'd bump the shoulder back another thou just to see.

 

[Terry O]

Maybe this chamber has a tighter neck???

If the body is .002" smaller at the web and the shoulder is bumped back .001" what else could it be?

I'd bump the shoulder back another thou just to see.

Yep, a .001 bump is often not enough.

 

[MDM]

I'm bumping mine back a good .0025. Make sure to take the fire control out of your bolt or remove your trigger to get a true feel for what is going on.

 

[lennyo3034]

Unfortunately, I have my die in all the way. Most I can bump it is .001". Sounds like I need to just back the barrel out a little bit.

 

[BRGUY]

If you can back the barrel out .002, I would think you should be good to go.