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Variances in Long Action DBM inlets

Earnhardt

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Minuteman
Jul 8, 2018
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OK, I have more questions than facts here...holy smokes there is a lot of variables in the long action DBM world...

Since there are many inlets for the Long action 700/Variants, I really don't know where to start

Please correct me if I'm wrong...

700 long action BDl inlet: takes a standard 700 BDL Bottom metal (no magazine), as well as other Detachable Bottom Metals that have been designed to fit into the BDL inlet.
Wyatt's makes a DBM that fits in a standard BDL inlet, but it has proprietary magazinesThe majority of them take AI style single stack magazines
HS Precision makes a DBM that drops into a standard BDL inlet, but it takes proprietary magazines
PT&G makes a DBM that drops into a BDL inlet, but it uses a ATI polymer mag
PT&G also makes a CIP DBM, but I can't figure out if it is a true drop into a BDL inlet or not. It does not use 3.850" CIP mags, it uses 3.775" AI mags

Standard M5 inlet: Range from a standard long action, to the 338 Lapua DBM which takes 3.715" AI mags
Then the 338 CIP DBM that takes the 3.850" AI mag
And finally the newer 338 CIP+/300 RUM DBM which takes a Accurate Mag that is 3.85", but neck area in the mag doesn't taper down as soon as the standard 3.850" 338 Lapua AI mags do. Because the 300 RUM mag case doesn't taper at the neck until after the 338 Lapua case does.

Surgeon/KMW: they have a proprietary DBM inlet that is not the same as the M5 inlet. The Surgeon/KMW inlet is larger than the M5, and to get the M5 DBM to fit into a Surgeon/KMW inlet, you need to fill in around the M5 DBM for a snug fit. The Standard Surgeon/KMW take the standard 300 win mag AI mags.
I can't find anything about the 1581 Surgeon DBM using 338 Lapua/ 338 CIP (3.850") mags

Gen 1 Seekins DBM with the push button mag release: Has a proprietary DBM inlet, that is not the same as a M5 inlet. The Gen 1 Seekins DBM takes standard AI mags. There is a Seekins Gen 1 338 DBM that took 338 CIP mags also

Gen 2 Seekins is a M5 inlet that fits the Havoc. I do not know if it is a M5 inlet.

Standard 300 win mag COAL is 3.625"... CIP COAL is 3.745"
338 standard COAL is 3.625".....338 CIP is 3.745"

Am I right here?
Seriously... hammer away fellas...

So if a guy wants to use a 300 wsm short mag in a long action, you need to use a AI style DBM, that takes 3.715" mags, but you need to use a 338 style mag because the AI 300 win mag is to narrow for the 300 wsm brass/neck taper?

And typically the 300 RUM and 338 (with standard or SAAMI chmabers are seated out to 3.9" or 4.0" so a DBM is for looks only then. (and yes, DBMs with mags look cool.) The gun needs to be used as a single shot. And if a custom reamer is used, such as a .250" freebore reamer in a 338 Edge, the loaded cartidge reaches 4.1"+ with 300 Bergers. Single shot only.

Please add info to this (and correct me if need be)
 
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