Minimum Headspace

[DoneNOut]

I set up my last 3 rifles with minimum headspace, the shoulders only blow forward .002 from factory brass length. I am seeing a noticeable difference, for the good, in my groups in all rifles. Granted, two have CBI barrels, but one is a factory Savage. First time I've done this, most chambers on factory rifles give .012-015 shoulder blow. My velocities are on par with what is usual for the cartridges, so is there a downside to setting minimum chamber spec?

In addition, I am also seating the bullets at slight touch of the lands, can still unchamber and no bullet movement.

 

[WeiserBucks]

Keep it up if it's working for you, no downside to what you're describing.

 

[DoneNOut]

You know what will drive a guy insane? Load developing for the rifles with min headspace for the first time and then having primers popping and exploding! Turns out I got a bad batch of WLR primers!

 

[1mechanic]

Only downside is if you get dirt in the action but I like it there it lessens the working of the brass.

 

[59FLH]

is there a downside to setting minimum chamber spec?

The only one that comes to mind is reloading size dies, I have needed to shorten the height on a shell holder before.

 

[1mechanic]

Mikecr, I believe he said he took new brass and measured all over the case and designed a reamer that was only ( and this is were I might not be remembering well ) 0.002" larger than the case and he doesn't even resize it because the spring back of the brass.

 

[ShtrRdy]

One gunsmith I use strives for minimum headspace and that works great.

A different gunsmith I use to chamber my benchrest barrels, (6mm PPC), likes to set up headspace about 0.003" back. Since we fire form brass to the chamber it works great too.

I suppose if you shoot mostly factory loaded ammo a minimum headspace chamber is a plus.

 

[MagnumManiac]

I chamber my own barrels and cut threads etc…I use .002" to set my headspace. I have a few chambers that are too short for the dies to bump enough, they each have their own shell holder with .010" turned off the top so that I can bump .001" and have minimum headspace, but I don't actually recommend this on anything but a comp high precision rifle in custom form. Brass gets larger each time it's fired and you run the risk of having hard chambering if steps aren't taken to prevent this.

Cheers.

 

[Veteran]

You know what will drive a guy insane? Load developing for the rifles with min headspace for the first time and then having primers popping and exploding! Turns out I got a bad batch of WLR primers!

If this continues to happen, you may want to think this over again.
At least in theory, not having much headspace and seating bullets at jam closer to the lands could increase initial chamber pressure? If your developed load is already pretty hot, this might be the bump on the margin that craters primers? Did you have some other way to confirm that the batch of primers was actually defective? Did the same thing in other rifles or something?

 

[DoneNOut]

If this continues to happen, you may want to think this over again.
At least in theory, not having much headspace and seating bullets at jam closer to the lands could increase initial chamber pressure? If your developed load is already pretty hot, this might be the bump on the margin that craters primers? Did you have some other way to confirm that the batch of primers was actually defective? Did the same thing in other rifles or something?

Oh yes. I got unlucky and got one of many bad primer lots put out by Winchester. They will blow pin holes through the edge of the primer. Got a claim in with Winchester and hopefully getting finalized today.

 

[Veteran]

Oh yes. I got unlucky and got one of many bad primer lots put out by Winchester. They will blow pin holes through the edge of the primer. Got a claim in with Winchester and hopefully getting finalized today.

Maybe they will send you some federals?

 

[Hugnot]

Fireform then almost zippo headspace (less than .003), anneal periodically - stripped bolt has slight resistance to closing. Don't use the bolt locking lugs & chamber as a press & F/L die. Keep ammo lots separated for each rifle of same caliber My ammo storage shelf is spread out far & wide (lots of rifles).

Winchester primers - I had a lot of Win 8 1/2's that had a loose slip fit in primer pockets that were nice & tight for CCI 200's. When I asked Winchester when that lot was manufactured, they responded by telling me that was "proprietary information" - bad move.

 

[cb186]

Go gauge plus a piece of Scotch tape as a feeler gauge. Light drag on the Scotch tape for a +.002" headspace.

 

[cajun]

Go gauge plus a piece of Scotch tape as a feeler gauge. Light drag on the Scotch tape for a +.002" headspace.

Just put together a 7mag remage and a savage 280AI. On the AI it worked great brass not moving much on initial firing. On the 7 mag since the gauges use the belt still had .018 case stretch on first firing. I'm not sure on a belted mag what you can do. I looked at using brass to set the headspace off the shoulder but from my research that wasn't recommended.