I was wondering what the difference is in 6mm cm barrel and 6mm cm match barrel by criterion. Are the chambers different? Is it a term used by criterion indicating that one is more refined? I tried googling it but didn’t see anything explaining what it is. Thanks
6mm creedmoor match barrel by criterion
- Thread starter jcmullis2
- Start date
In something like the .308 or .243 a "match" chamber can show some improvement. In the creedmoors, the SAAMI spec chamber is a functional match chamber already.
My guess is the freebore is just shorter on the match chamber for seating VLD/ELD/A-Tip style bullets near the rifling at magazine length. The SAAMI chamber isn't sloppy by any means, just has a longer freebore, and in my experience they're pretty lenient on seating depth.
My guess is the freebore is just shorter on the match chamber for seating VLD/ELD/A-Tip style bullets near the rifling at magazine length. The SAAMI chamber isn't sloppy by any means, just has a longer freebore, and in my experience they're pretty lenient on seating depth.
I was thinking it might be something like that too. I’m just not sure and figured someone here might know for certain. I appreciate your thoughts on this.
That’s the saami 6creed reamer it appears. You have one they call match?
With a leade of .183 and a throat length of .200, that is very generous. More like what it should be in a number of other cartridges.
In the broad transition in the shooting world to longer bullets, there are those still calling the shots that think we need to have shorter freebore and throats. That's because they don't seem to know the difference between short benchrest bullets and long sleek long-range bullets. What's accurate with a short bullet won't work with a long bullet. Mostly because it puts them too far back in the case.
In the custom world this is recognized and good long-range smiths are freeboring and throating to match the long bullets needs.
I purchased a Criterion match barrel from NSS for my 243 Win. I emailed Criterion asking me about the match chamber. They sent me a copy of the PTG chamber reamer they used and it is marked “243 Win CBI Long Throat”. The only difference I can find from the SAAMI drawings is the throat length. SAAMI is 0.1774” and the PTG drawing lead/throat is 0.224.
Mike
Mike
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Those measurements sound like what Savage uses, My first go around with a 6 CM, I diffently did not have to worry about the full Cal. of any 105 the 115's being below the neck / shoulder junction.
If considering a Pre Fit, I would contact the others offering Pre Fit's and ask them if they will cut the chamber to your Spec's ; ie; send them some "dummy Rounds" and you want the bullets to, hit the rifling, be ___ thousands off, ect.
There are a bunch of them, either by gun smith's or by the barrel makers them self's. Just depends on how much the OP wants to spend.
NSS/ Criterion has has everything, barrel , lug,nut,and an action wrench that holds the lug in place. All the others just offer barrels, a few offer nuts .
The fella that took my order at northland was very knowledgeable and helped me a bunch. I had no idea of how much leade and such so he asked me if I reloaded or if I planned to use factory ammo. I told him I do reload but that I planned to use factory Berger ammo with its Lapua brass at times and reload my fired brass. He recommended a .18? leade because of that and I deferred to his expertise. I may have screwed up and my barrel won’t last as long but live and learn, right. I just don’t have any custom barrel experience and most lessons aren’t free.
In the past I’ve never knowingly exceeded specs listed in my Lyman manual, the labels on various propellants or the pamphlets included with the reloading dies. However the creedmoors aren’t in my old reloading manuals so I’ll be relying on information primarily from the internet. No problem there because I do know enough to ask questions when I don’t know. Mainly because I really don’t wanna have a catastrophic failure and blow my face off. I thank you and everyone for the much needed help.
That's Jim Briggs. I've bought barrels from him too and yes he is knowledgeable. Added: my Shilen 7mm-08 Barrel I bought from him had a long leade and it's lasted over 4k so far.The fella that took my order at northland was very knowledgeable and helped me a bunch. I had no idea of how much leade and such so he asked me if I reloaded or if I planned to use factory ammo. I told him I do reload but that I planned to use factory Berger ammo with its Lapua brass at times and reload my fired brass. He recommended a .18? leade because of that and I deferred to his expertise. I may have screwed up and my barrel won’t last as long but live and learn, right. I just don’t have any custom barrel experience and most lessons aren’t free.
In the past I’ve never knowingly exceeded specs listed in my Lyman manual, the labels on various propellants or the pamphlets included with the reloading dies. However the creedmoors aren’t in my old reloading manuals so I’ll be relying on information primarily from the internet. No problem there because I do know enough to ask questions when I don’t know. Mainly because I really don’t wanna have a catastrophic failure and blow my face off. I thank you and everyone for the much needed help.
No, you didn't screw the pooch.
Damn nice guy. I highly recommend nss and that’s solely because of him. I told him what I had and what I wanted to do. He made sure that I had everything I needed to get the job done. Some stuff I had and some I didn’t. The stuff I didn’t have I bought from nss. I can’t think of one thing I bought that was available at a better price somewhere else. Awesome customer service and these days that’s a rare thing.
I’ve gotten two long leade 260 Shilens from them.
both have been excellent.
It’s good to hear I’m not the only one and that the barrel will last a while.
If I was a competition shooter and wasn’t a cheapskate $100 for 100 rounds of new Lapua brass probably wouldn’t bother me. However a few hundred rounds of empty Lapua brass costs more than the barrel. Later on I can probably replace the barrel with just the money I save on brass and still use the brass I prefer. It’s hard to beat free Lapua brass that’s already fire formed for the rifle.
Bad math. When you consider the lapua will almost certainly outlast domestic brass, and require zero truing/ sorting, it comes out cheaper.
The .180 freebore will work fine for most bullets, although not ideal for the 105 hybrid. If you’re a cheapskate though, you should be looking at the 108 ELD or 115 DTAC anyway. Cost aside, I’d still pick the 115 over anything.
Agreed. Lapua is worth the money in accuracy and dependability 5-6-7--10 times down the road reloaded. That's a thousand rounds with just that many reloads.
If you go with cheap brass, you'll be getting 5-6 reloads. So buying twice at two thirds the price is not a money saver.
The question always begs if you can get your new barrel close enough to your old one so you don't have enough headspace difference to start causing incipient case head separation. Incipient meaning it's going to happen. On some of my cartridges, I didn't catch it and it DID happen. So, when you re-barrel, make sure you are not having head-space or other 'space' issues. A max diameter chamber will cause the same thing. My suggestion is to get your own reamer and talk to your gunsmith when you rebarrel so you can copy what you have closely as you can.
That’s why I like barrel nuts.
I can set headspace dead nuts.
I killed two Shilens with a batch of 250 cases and got well into a third before that brass finally died.
A lot of mention of the .183 freebore .On the diagram it shows .200 Lead + .183 Throat, or .383" from the case mouth to where a 6MM bullet will touch the lands. I just measured my 6CM's 115 DTAC dummy round I use for seating and form the case mouth to where the bullet measures .2345" is .3395.
Just saying that the ".183 freebore is a bit misleading.
Just saying that the ".183 freebore is a bit misleading.
You’re reading it wrong. Look again. Freebore is .183. The .200 call-out is the freebore plus the 45 deg transition at the end of the chamber.
I don’t follow you. I’m still getting Lapua brass. As I’m sure you know Berger uses Lapua brass in there ammunition. I bought a couple of boxes of 95gr and 105gn factory Berger ammunition to break in my barrel and such. It’ll be fire formed by my rifle and after a little case prep ready to reload.
I’ve read a little about the 115 DTACs and they have great reviews. For starters I’ll be trying your suggestions of the 115 DTACs & 108 ELDs, and I’m thinking maybe some 95 & 103 ELDs just to round things off.
I’ve got a couple of pounds of h4350 but I’m definitely open to any suggestions you may have. I’ve never loaded 6mm cm and need all the help I can get. I can tell you know what you’re talking about and I appreciate your help.
I see now, and misunderstood your post. That lapua brass though isn’t free, you paid handsomely for it. I think most people around here would advise you to get right to it by picking the bullet you WANT to shoot and developing a load for it as quickly as possible, since your barrel likely won’t last that long. In other words, you don’t need to test 4 bullets. If the first one works, roll with it. I like the performance and cost of the 115 and typically try it first. I pretty much never make it past the 115’s. Haven’t found a barrel that doesn’t like them. H4350 is good stuff. These days I like rl16 better. The secret is out though and its getting hard to find now too.
What twist is your barrel? They only had the 1:8 in stock so I grabbed it up. Like I mentioned earlier I’m new to the 6cm and don’t know if the 115s or 108s will like a 8 twist barrel. I would have preferred a barrel with a 7 or even a 7.5 twist but didn’t wanna wait. The fella at nss said it would do fine with the long heavies but only time will tell.
I have a 6.5cm also that’s why I have the h4350 and was thinking about some rl17 for a bit more mv but the rl16 actually looks as good or better.
I’ve got a bunch of CCI br4 primers but I’m interested in what you’re using.
Appreciate your insight into this.
I have a 6.5cm also that’s why I have the h4350 and was thinking about some rl17 for a bit more mv but the rl16 actually looks as good or better.
I’ve got a bunch of CCI br4 primers but I’m interested in what you’re using.
Appreciate your insight into this.
Sounds like I’m heading in the right direction at least. I’m gonna pick me up some RL16 in a few days when I order some other stuff I’ve been wanting. Thank you kindly for sharing your expertise.
POTATO / POTOTO when I use the Hornady 6MM gauge that I use to measure total loaded round length so I can experiment with different bullet jumps
I get measurements from the case head to where the bullet hits the lands. I also used to use a set up to measure and sort by total bearing surface of bullets. A trick I learned at Quantico .
Back to my point, when I measure the total length of a loaded round that the bullet has been loaded to touch the rifling , and I measure from where the bullet marks on the lands to the case mouth, I call that "free bore" . I only concern myself with the throat's ID.
No he doesnt get basic math, hes a marine.
EDIT: Actually, fuck, its not even math, its just plainly written.
Still figure he could get a handle on the fact that the arrows are there point to it for him...
The beginning of the leade/end of the freebore is .2 from the end of the chamber neck. It is .183 from the end of the neck transition/beginning of the freebore to the end of the freebore. Thats a difference of .017 between the two for the angled transtition , not a combined sum, as was already explained by subes. Its freebore is .183, and just because you dont understand that doesnt change the definition of freebore.
So its not "POTATO/POTATO"
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