3.715 MDT Mag not Fitting in Hawkins M5 DBM

[Pmurri1]

I recently Built a Custom Rifle with a Proof Barrel, Manners Stock, Lone Peak Fuzion Ti, and hawkins M5 DBM bottom Metal. It is chambered in .300 Win Mag. I Recently purchased an MDT 3.715 Magazine for it and the magazine will only lock in to the bottom metal if the action is open, Once the action is open and the Mag is locked in then the bolt will no longer close. Any thoughts on what i need to do to fix this? is something not adjusted right? Maybe a bad Mag? Maybe need a different brand? Bad bottom Metal? IDK

 

[Evintos]

- Wrong latch height, you'd need the standard height for AICS
- Wrong pillar height (too short) <- I think this one is the most likely, short video below.
- Magazine feed lips require adjustment

 

[Mike Casselton]

He's probably correct.

To test this, remove the bottom metal and add a washer or two between the BM and the stock. Do this front and rear.
Tighten it back up and reinsert the problematic mag.

If anyone knows the actual difference in mag latch height, please post it.
Then the OP can try and match that with the washers.



OP, once you determine if this is the case, then you'll know to order the correct mag latch.

 

[Terry Cross]

I recently Built a Custom Rifle with a Proof Barrel, Manners Stock, Lone Peak Fuzion Ti, and hawkins M5 DBM bottom Metal. It is chambered in .300 Win Mag. I Recently purchased an MDT 3.715 Magazine for it and the magazine will only lock in to the bottom metal if the action is open, Once the action is open and the Mag is locked in then the bolt will no longer close. Any thoughts on what i need to do to fix this? is something not adjusted right? Maybe a bad Mag? Maybe need a different brand? Bad bottom Metal? IDK

My money would be that your Z-axis (pillar height) height is incorrect.

Every DBM style bottom metal out there has a specific offset dimension for its distance below the receiver.
Your Hawkins probably came with that dimension listed or if not, they can advise you via email, etc.

Ignoring it will place (or in your instance, attempt to place ) the magazine at the wrong point in space relative to the receiver bottom and bolt path.

Some people will try to make their bottom metal fit flush with the bottom of the stock and just ignore this dimension.
A correctly programed stock inlet will base everything off of the specific brand of DBM style bottom metal and then adjust the receiver/barrel channel inlet at the appropriate distance from the bottom metal. The centerline of the receiver sitting 10 to 50 thousandths above the top waterline of the stock is not uncommon and nobody notices. It gets lost in the noise because the ejection port cut, bolt handle cut and bolt release cut (if your action has a side mounted stop) is adjusted up in unison with the main action inlet.

I would wager to say that 95% or better of the issues with mags not locking in or guns not feeding properly are due to this being ignored or done incorrectly.
This dimension is non-negotiable. Hawkins makes very good quality hardware and MDT makes very good quality magazines. While either company could possibly ship something out of spec, my bet is they didn't.

God only know how many mag latches have been altered or special ordered and how many perfectly good magazine lips have been bent in an attempt to fix what should not have needed fixing.

So.... I would suggest getting the correct Z-axis (pillar height) dimension from Hawkins and then measuring your actual front and rear heights.
I will bet both are too short.
Don't scour the internet and don't use another brand's published pillar height. Contact Hawkins directly if the dimensions weren't included with your hardware.

./

 

[B'N'F]

My money would be that your Z-axis (pillar height) height is incorrect.

Every DBM style bottom metal out there has a specific offset dimension for its distance below the receiver.
Your Hawkins probably came with that dimension listed or if not, they can advise you via email, etc.

Ignoring it will place (or in your instance, attempt to place ) the magazine at the wrong point in space relative to the receiver bottom and bolt path.

Some people will try to make their bottom metal fit flush with the bottom of the stock and just ignore this dimension.
A correctly programed stock inlet will base everything off of the specific brand of DBM style bottom metal and then adjust the receiver/barrel channel inlet at the appropriate distance from the bottom metal. The centerline of the receiver sitting 10 to 50 thousandths above the top waterline of the stock is not uncommon and nobody notices. It gets lost in the noise because the ejection port cut, bolt handle cut and bolt release cut (if your action has a side mounted stop) is adjusted up in unison with the main action inlet.

I would wager to say that 95% or better of the issues with mags not locking in or guns not feeding properly are due to this being ignored or done incorrectly.
This dimension is non-negotiable. Hawkins makes very good quality hardware and MDT makes very good quality magazines. While either company could possibly ship something out of spec, my bet is they didn't.

God only know how many mag latches have been altered or special ordered and how many perfectly good magazine lips have been bent in an attempt to fix what should not have needed fixing.

So.... I would suggest getting the correct Z-axis (pillar height) dimension from Hawkins and then measuring your actual front and rear heights.
I will bet both are too short.
Don't scour the internet and don't use another brand's published pillar height. Contact Hawkins directly if the dimensions weren't included with your hardware.

./

Terry hit the nail on the head - a lot of people tend to over-look the relationship between the pillar height, and the magazine latch relationship. Check to see if the mag is bottoming out on the bottom of the action prior to the latch retaining the magazine - if it is, then you know without a doubt that the pillar height is too short, alternatively, if the mag is being retained by the mag catch, but can be pushed further "up" into the mag-well, then the pillar height may be too long.

If I recall correctly, Hawkins long action dbm calls for a front pillar height of approx. .670"