Primers during Fireforming a BRX

[Bob3700]

Gents,

Recently I chambered a bbl for the 6mm BRX cartridge. THe brass used is Lapua, powder Varget, 107 SMKs and Wolf primers.

The fireform method used was the false shoulder method and the often recommended load of 30 gr of Varget with the bullet .010" into the lands.

Bolt life was normal and the primers are not flattened. The primer imprimt is something else. The normal dimple of the firing pin is very shallow and flowing back around the pin and into the bolt hole itseld. If this was normal ammo,after fireforming) I would simply think my firing pin hole is too large. This unit has not been bushed to the smaller .062" diameter.

In your opinions, what am I looking at here? Is this simply a firing pin hole that is too large?

The action is a Rem 700 converted to a single-shot.

I have photo's but they are too big,4.2 mgs) to load.

RGDS

Bob

 

[Forum Boss]

Everything Donovan says is 100% correct.

In addition, if your false shoulder was a little short, creating something less than a solid crush fit, this can allow some cartridge movement during fire-forming. This can worsen the primer flow situation,it's kind of complicated to explain).

Check again after shooting some fire-formed cases. It may take a couple firings to get fully formed shoulders. At that point you may find that the primers look more "normal" after firing. Bushing the bolt is a good idea, but you may discern it is not necessary with the fire-formed cases.

Also, German Salazar and others believe the Wolf Small Rifle primers ARE on the soft side. He strongly recommends using the Wolf Small Rifle Magnum primers instead. You didn't mention which type you used.

Re photos: If you go to www.irfanview.com you can download FREE image editing software that will allow you to easily re-size your images. 600x480 or 800x600 is a good size for this Forum.

 

[Bob3700]

Don and All,

The primers used with the standard Wolf SR variety.

Bob

 

[Rustystud]

Bob:

I have had a lot of burn throughs with Federal 205s during fire forming. John had very irratic ES and burn throughs with Wolf. I would use Remington or Winchester during the fire forming.
Rustystud

 

[spclark]

The small rifle KVB primers - now what Wolf sells I believe - are indeed very soft. The magnum variety are supposed to have the same charge weight but a tougher cup metal.

I used to use the KVB223 in .223 & 6.5 Grendel & invariably loads that would leave CCI or Federal primers barely flattened would cause the KVB metal to crater as you've described.

An un-bushed firing pin hole will show up problems like this that much sooner.

Thanks for the link to Gretan BTW dmoran; I have a Quadlite bolt I want to get bushed & was wondering whom to trust with this operation.

 

[davek]

I use the ccibr or the magnum primers, jam the 107, or 105's in the lands, my bolt is bushed and the load is 27, to 28 grains of varget, this is the firing forming load i use for practice and it works every time, after the brass is resized just use fullpower loads and your good to go. Davek.

 

[Bob3700]

Steve,

I was under the impression,perhaps false) that the Quadlite action had the smaller firing pin assy. Let me know if I am wrong as I too have a Quadlite that I will be prepping over the Winter as a switch bbl gun. 6XC and 6 BRX bbls.

Bob

 

[Travelor]

Standard small rifle Wolf primers are SOFT.

Switch to Magnum small rifle Wolf primers and it will solve your problems. Supposedly the priming compound is the same, just a harder cup.

Was having the same problems and this change curried it.

 

[BradY]

My false shoulders were too short and the cases had to be sat under the ejector claw so they didnt back onto the bolt face. Seems to be working so far. But im also using CCI BR primers and they have a hard cup. Maybe do the case under extractor trick and go to a harder cup primer.