I probably shouldn’t be surprised by this, but I must say that I am. Just wondering if any of you guys have experienced anything like this, and if so, have any advice for my reloading.
In short, I have two Bergara 6.5 PRC rifles, and I just discovered that the heads space is different for each one. I first bought the Bergara B-14 Squared Crest 2 years ago and I love it. I loved it so much so that I bought a second Bergara (this time a Widerness Ridge) chambered in 6.5 PRC with the intent of putting it in an MDT LSS XL chassis (which I did just recently).
So, I took some old Nosler brass and resized it with the exact same shoulder bump that I use for the B-14 Squared Crest and assumed it would fit into the newer rifle (the Wilderness Ridge that I just put into an MDT chassis). In short, the resized brass fits like a glove in my Crest, but does not fit in the Wilderness RIdge/MDT.
-The brass started out at 1.633 before resizing.
-It was 1.631 after resizing, fitting nicely in the Crest, but does not fit the Wilderness Ridge/MDT.
-I experimented with a piece of brass and bumped it down to 1.627 and it fit comfortably in the Wildreness Ridge rifle.
I’m not surprised that they are different, but I am a bit surprised at how big the difference is. Is that normal? And, if I load to the smaller tolerance of the Wilderness Ridge (1.627), will this have an impact on my accuracy in the Crest (which works well at 1.631)? I’m hoping I don’t have to create two separate brass sizes for the two rifles.
Interesting. I haven’t measured two headspace’s from any same company to compare before.
I will say that companies have had to change their reamer specs many times over the last few years with the prc cartridges to avoid going over pressure. Maybe this is a case of a change to respond to an issue rather than just poor consistency?
Thanks Jim. If I load for both of my rifles at the smaller/tighter headspace (1.627), do you think this will impact the accuracy in the rifle that like it set at 1.631?
Thanks Carter! Yeah, you’re right, you can’t measure it with the hornady guages. But, I just kept bump the shoulder down until it fit comfortably in the new rifle. Once I got that, I just measured the case. If there is a better way to investigate what’s going on I’d love to know.
And thanks for the SAAMI info, I didn’t know that. That’s a big enough range to account for what I’m seeing.
The smaller case may shoot fine in the larger chamber, so you may very well be able to use the same setting for both, I would try it, just makes your loading simpler.
I have good data on on how my first (longer head space) Bergara groups with the longer head spaced cases. As such, I loaded 12 rounds (for 4 three shot groups) to test out how it will now shoot with the smaller head space cases. I’m assuming and hoping I won’t see a significant difference with the new loads. If I don’t see significant difference, I’ll just move forward with both rifles with shorter head spaced cases. If there is a significant difference, I guess I’ll have to size the brass differently for the two rifles.
Their claim is very dubious, and only applies to comparing your measurement with other people that have the same set. The Whidden case gauges are the only ones I know of that will give you a consistent measurement, and they calibrate them against a ‘go’ gauge.
I have two Weatherby Vanguard 7mm-08. They both use the Redding competition shell holder 0.08 for head space (shoulder bump). But the brass expands to different widths in the chambers. If I fire one shot in each rifle and then try to move the fired casing from one gun to the other, the casing fired in the Camilla won’t fit in the chamber of the other gun, but the other gun’s casing will fit in the Camilla. So, I’m witnessing a difference in width not length of the chamber.