I'm not sure how many different designs there are for the 300wsm? What makes them better or not as good when it comes to chamber, throat or other aspects? With different manufacturers chambering their own barrels/rifles how do they decide? Other than customized/optimized for a specific bullet what else is there? I can add to the throat if needed, but in @bamban 's 7rm nez/ni thread got me thinking! The angle of attack (N dimension) could be a deciding factor? This is for an AR w/11T for up to 185's and limited to 2.830". With some makes having to choose "custom" for chamberings might have me going 300rcm or 300saum instead! WSM is because of finding brass and dies for it are easier. Any other info would be appreciated!
reamer decision(s)
- Thread starter ARlife4me
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QuietTexan
Well-Known Member
Unless specified I would think most shops are using the standard SAAMI-spec reamer. 300 WSM doesn't have a history as a wildcat before being standardized to create legacy reamer issues.
Are the ones listing it as a "custom" option doing that because they have to rent it instead of having one maybe? If it's a $25-35 fee that's in line with the cost to rent reamer and gauges for a job.
Approved drawings of 300 RSAUM, 300 RCM, and 300 WSM attached:
Are the ones listing it as a "custom" option doing that because they have to rent it instead of having one maybe? If it's a $25-35 fee that's in line with the cost to rent reamer and gauges for a job.
Approved drawings of 300 RSAUM, 300 RCM, and 300 WSM attached:
QuietTexan
Well-Known Member
Yeah that's what I'm asking, I've never used BA so I don't know about what all they make. WSM isn't very common in the AR world so it wouldn't surprise me if a company that makes primarily AR barrels doesn't keep one around.
I was asking because McGowen has a list of standard SAAMI chambers they'll cut into barrels, but for a $60 fee they'll do chambers not on their list by renting the reamer. 300 WSM is not on their standard chamber list for AR-10 but is for bolt action, maybe they'd work with you on that one.
I was asking because McGowen has a list of standard SAAMI chambers they'll cut into barrels, but for a $60 fee they'll do chambers not on their list by renting the reamer. 300 WSM is not on their standard chamber list for AR-10 but is for bolt action, maybe they'd work with you on that one.
Doesn't quite seem fair does it!
MagnumManiac
Well-Known Member
I have ALWAYS rented or bought 'Match Grade' reamers, they are at minimum SAAMI spec, not outside SAAMI spec as I have been told by customers. For instance, my Weatherby reamers are all Match Grade, but, here's the big but, they are to proprietary specs, so before SAAMI but held by CIP. They have non-traditional length throats as originally designed by Roy Weatherby, so the 270 Weatherby has a parallel sided .0005" .376" throat, the 300, 340 and 375 all have a parallel sided .0005" .500" throat, the leades vary due to calibre size, but you get the drift, also, all CIP reamer prints for the Weatherby line are metric, converted to imperial.
I fully believe you get a far better chamber when using match grade reamers with custom throats, or throating reamers to customise the throat to your needs.
Matching sizing dies can be a struggle, as a few of my custom chambers have had to have modified shell holders just to size the brass enough, but shell holders are cheap…
As far as I can see, there are no special reamers like you mention, but for a SAAMI chamber and throat, is probably all you need, unless you want a Match chamber.
Cheers.
I fully believe you get a far better chamber when using match grade reamers with custom throats, or throating reamers to customise the throat to your needs.
Matching sizing dies can be a struggle, as a few of my custom chambers have had to have modified shell holders just to size the brass enough, but shell holders are cheap…
As far as I can see, there are no special reamers like you mention, but for a SAAMI chamber and throat, is probably all you need, unless you want a Match chamber.
Cheers.
I was just wondering after seeing various reamers for 6.5creed and 6.5x284win vs 6.5x284norna. With the chamber improvement of the 223wylde over 5.56nato for example of the possibility of the 300wsm? I guess the wsm changes are how it's throated by makers if any?
MagnumManiac
Well-Known Member
As far as I can tell, special reamers for the WSM cases is rare, but that does not mean you can't draw one up, or use a SAAMI reamer and custom throat it… I rarely ever use a reamer without custom throating for a certain bullet.
Due to the short action, throats on the WSM are short, but like I did back in 2000/1 we used standard 3.4" actions and built 25/26/28/33 on the 300WSM case, we could throat as short or long as we required.
Just as a side note, the 6.5-284 Norma is far superior than the 6.5-284 Win wildcat due to throat length…
Seeing that the WSM uses a 35° shoulder, you will get no improvement with a 40° shoulder because the case is already very straight.
Cheers.
QuietTexan
Well-Known Member
Maybecall KAK and Manson? To get it straight from the guys doing exactly what you want to do.
KAK would be able to tell you if they use a SAAMI spec or not in their barrels, and Manson (Or JGS, PTG, Clymer, whoever) would know how many variations of the print they've made.
I would expect you to hear that most of the changes to the spec design are longer throats to run the WSM in medium and long actions. Like he said ^^^ it's already pretty short to start with.
TL;DR none of the specific things you mentioned really compare to 300 WSM in an AR. But my opinions because I'm opinionated:
For 300 WSM since it was designed to run in a short action you should be fine with spec throat length. I don't think you'd be able to use anything longer because COL/ mag restriction.
That's an assumption though because I've only used factory loaded ammo in my KAK 300 WSM, I've never bothered to check the throat on it. I'll order a modified case and try though.
300 WSM was never a wildcat so doesn't apply here, you won't find any pre-certification reamers, dies, brass, etc floating around.
Nothing to gain here in the 300 WSM because it already has a good throat design to start with. It never got changed to suit full-auto fire, but that would be kind of cool to have to change the throat design if an M240 could be modified to handle it
KAK would be able to tell you if they use a SAAMI spec or not in their barrels, and Manson (Or JGS, PTG, Clymer, whoever) would know how many variations of the print they've made.
I would expect you to hear that most of the changes to the spec design are longer throats to run the WSM in medium and long actions. Like he said ^^^ it's already pretty short to start with.
TL;DR none of the specific things you mentioned really compare to 300 WSM in an AR. But my opinions because I'm opinionated:
Shorter than spec throat lengths are most common, .169 or even .110 instead of the .199 SAAMI spec. Hornady was generous in the design, and as soon as it landed guys were trying to get a 0.020" jump. Anything shorter than .199 SAAMI and factory 140gn-ish ammo might not work.
For 300 WSM since it was designed to run in a short action you should be fine with spec throat length. I don't think you'd be able to use anything longer because COL/ mag restriction.
That's an assumption though because I've only used factory loaded ammo in my KAK 300 WSM, I've never bothered to check the throat on it. I'll order a modified case and try though.
The Win was a wildcat for a long time before Norma changed the print a touch and got it certified. Most old designs are short throated, but not all of them. I got my reamer made on a Win print with a longer throat because I wanted to shoot the Berger 153.5s but didn't want to re-tool dies for it. What Norma did only matters if you want to use factory loaded ammo, the Win worked great for a long time before CIP papered it.
300 WSM was never a wildcat so doesn't apply here, you won't find any pre-certification reamers, dies, brass, etc floating around.
IMO this was a backtrack in the 5.56 design to regain accuracy that was intentionally given up for automatic fire reliability. I've always thought there wasn't ever any advantage to the 5.56 NATO outside of full-auto usage, because that was the goal FN was working towards when they did it. Sure the 5.56 got certified at a slightly higher pressure (or not, CIP vs SAAMI, that whole mess), but that didn't translate to anything useful. The entire point was reliability and extending the max effective range of the Minimi. Which my opinion again the range increase was a result of changing to the 62gn penetrator, and the larger throat was all about reliability. The hybrid Wylde chamber allows for use of newer ammo specs like Mk262 without the (comparatively) terrible accuracy of M855 in the Minimi.
Nothing to gain here in the 300 WSM because it already has a good throat design to start with. It never got changed to suit full-auto fire, but that would be kind of cool to have to change the throat design if an M240 could be modified to handle it
Rflshootr
Well-Known Member
I don't know a single thing about AR's other than which end the bullet comes out of. With that said, the best way to spec a reamer for a bolt gun is, to have a few fired cases on hand and size them in the die that you will use. Send 2 to Manson with the bullet you want to use, seated to the length you want. Also send 3 more sized with no bullet. They will take the measurements and grind the reamer to match your die so the brass isn't over worked. At the same time, they will determine the free bore needed and grind to that as well. Let them know it is for an AR in case the rear of the chamber needs to be made slightly bigger for feeding purposes. Again, I don't know Jack about AR's.
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