What Brand or Model Has the Best Chassis Inlet?

[samb300]

I'm curious for those out there that have tried a multitude of R700-pattern chassis systems, which one(s) have the best inlet? By best I mean the most consistent for fitting a variety of actions, the best clearance for triggers and trigger hangers, and overall the best fit. Are there chassis that place unwanted stress on the action as it is torqued down? Or have spotty recoil lug contact? Is there a chassis that you can take the barreled action out of, put it back in and the zero will be practically the same?

I realize there isn't any one perfect inlet for every R700-pattern action out there. And I'm not asking for anyone to bash any company. I'm used to the flat-bottom, square AI action, so I don't have any knowledge of the round R700 actions. I've read things like the AI-AICS chassis is good, but requires machining relief for certain actions and triggers...info like that is what I'm looking for.

Thanks,

Sam

 

[Threadcutter308]

Do you have an action now ? If so, what is it ? What stocks are you considering ?
I think the same question has been asked here in about the last 24 hours. Without more information from you, you're going to end up getting flamed by other Hiders that are tired of seeing the same questions without any information so that the responses can be narrowed down.

Now, on to being helpful; I have fit Bighorn TL-2's, TL-3's with Manners T2-A's/Mini-chassis with no issues. They drop right in. I have fit Ultimatum Deadlines with Manners T2-A's/Mini-chassis and they have to have the Mag release shortened and re-curved for AICS magazines. That is not the fault of Manners or Ultimatum (or AI for that matter). It's just one of those situations where some minor fitment is necessary.

 

[jcmullis2]

Krg chassis’s accepts whichever R700 barreled action I’ve used without any problems. I’ve used every model from the bravo to the whiskey 3. Hope that helps.

 

[ddridan]

From the experience of myself and buddies, MPA has a very forgiving inlet. Between us we’ve had Impacts, Bighorns, Defiance Deviants, and Ultimatum Deadline actions in our MPA BAs. The trigger hangar area is big enough to fit the Deadline without fouling which sits lower than most due to its oversized bolt body.

 

[samb300]

Krg chassis’s accepts whichever R700 barreled action I’ve used without any problems. I’ve used every model from the bravo to the whiskey 3. Hope that helps.

Thanks! Do you know if the inlet is identical for the Bravo and W3?

 

[samb300]

From the experience of myself and buddies, MPA has a very forgiving inlet. Between us we’ve had Impacts, Bighorns, Defiance Deviants, and Ultimatum Deadline actions in our MPA BAs. The trigger hangar area is big enough to fit the Deadline without fouling which sits lower than most due to its oversized bolt body.

Appreciate it. Yeah I’ve heard the Ultimatum can cause issues, good to know the MPA works well with it.

 

[samb300]

Do you have an action now ? If so, what is it ? What stocks are you considering ?
I think the same question has been asked here in about the last 24 hours. Without more information from you, you're going to end up getting flamed by other Hiders that are tired of seeing the same questions without any information so that the responses can be narrowed down.

Now, on to being helpful; I have fit Bighorn TL-2's, TL-3's with Manners T2-A's/Mini-chassis with no issues. They drop right in. I have fit Ultimatum Deadlines with Manners T2-A's/Mini-chassis and they have to have the Mag release shortened and re-curved for AICS magazines. That is not the fault of Manners or Ultimatum (or AI for that matter). It's just one of those situations where some minor fitment is necessary.

Thanks for the info on the Manners. I have heard elsewhere the mini-chassis fit really well.

My intent wasn’t to ignorantly post what has already been posted before. I think I post enough and have a positive enough footprint on SH that people would know I’m not trying to waste space. My question is vague because right now my mind is open to what products work best for the widest variety of actions. Why I’m asking is still open at this point, maybe I have an action and chassis in mind, or maybe I don’t.

 

[spife7980]

Thanks! Do you know if the inlet is identical for the Bravo and W3?

They share the same backbone

 

[jcmullis2]

Thanks! Do you know if the inlet is identical for the Bravo and W3?

Yes it is, as Spife7980 said they share the same backbone. IMO that makes the Bravo a darn good value.

 

[morganlamprecht]

Thanks! Do you know if the inlet is identical for the Bravo and W3?

idk bout the bravo, but the w3 wont fit an impact w/ its hanger

 

[samb300]

I'm not sure if you're asking about fit in terms of bolt handle cut out, ejection port, bolt release type of accuracy of individual action size and shape fit or specifically the inlet/ bedding surface in terms of stress fee action fit. I can't be really too helpful on the former bc it really seems to vary brand to model. But for the latter...

I've used Manners, XLR, KRG, and MPA. It seems like most of them use a V block with an unsupported tang. I really don't understand why this seems to be the most popular method, other than I think it was the earliest machined block inlet used. The way I understand the theory of it's fit is that the left and right sides of a round bottomed action ride on the long "V". The problem with this is the tang is unsupported and that's 1 of 2 torque points.. the front action screw will pull the action into the V without stress, but when you begin to tighten the tang screw....how much torque can you give it before it starts to bend the tang? This is why Manners recommends 65 front and 45 rear.

This is why I like MPA's technique better. If you look in between the side of an action bolted in an MPA chassis, in between the action and the chassis you'll see daylight. The action is supported on platforms under the front action screw and rear/ tang action screw areas and free floats every where else. No bannana torquing to occur. MPAs have lower sidewalls to eliminate varying bolt release reliefs and ejection port lengths. And they have an adjustable mag catch latch to give the user the ability to adjust mag seating height which causes a large majority of custom action feed/ tuning issues.

Thanks for the info, I really appreciate it. I didn't realize that the rear tang is commonly unsupported...seems like an odd design choice but I don't know the origins of why it would've been done in the first place. I'll have to look at an MPA more closely.

I'm thinking about it more from an inlet/bedding perspective, under the assumption that trigger, ports, and safety clearance could be designed or modified more easily. Really I'm trying to determine what inlets work the best for if/when I go down the path of designing a stock on my own.

 

[THEIS]

Hi,

Maybe a split (upper/lower) center section of the chassis so that user can remove the lower section and access trigger, magazine latches, etc while allowing the upper section to utilize the glue and screw method for bedding. It would eliminate all the issues of supported vs unsupported. It would solve the round vs V block debate.

Sincerely,
Theis

 

[samb300]

Hi,

Maybe a split (upper/lower) center section of the chassis so that user can remove the lower section and access trigger, magazine latches, etc while allowing the upper section to utilize the glue and screw method for bedding. It would eliminate all the issues of supported vs unsupported. It would solve the round vs V block debate.

Sincerely,
Theis

It's not a bad idea, but most of the guys I know with R700-pattern actions swap them in and out of stocks so frequently it would make your head (and wallet) hurt lol

 

[ddridan]

It's not a bad idea, but most of the guys I know with R700-pattern actions swap them in and out of stocks so frequently it would make your head (and wallet) hurt lol

Plus becomes a bit of a root to swap barrels without a quick change system if the action is glued AND screwed if barrels didn’t wear out 100% I’d utilise a glue method.

 

[samb300]

From the info I've gathered so far, the Manners Mini Chassis is the only inlet that seems to confirm the rear tang is floating. Manners calls out 65/45 for a front/rear torque.

MDT, MPA, XLR, and KRG all call out 65/65 F/R. AI-AICS calls out 53/53.

I don't know if that means the rear tang is in perfect contact on those inlets? Or if possible there is still some rear tang float?

 

[spife7980]

I've used Manners,

Just one point- Manners had the raised bolt tang support for awhile now, no?

I know my krg doesnt as I had it out recently enough to fresh memories, not sure of the mdt or xlrs, never paid attention to it.

 

[samb300]

Just one point- Manners had the raised bolt tang support for awhile now, no?
View attachment 7408490

I know my krg doesnt as I had it out recently enough to fresh memories, not sure of the mdt or xlrs, never paid attention to it.

Is that the Gen 2 MCS-DBM Mini Chassis? I'm struggling to find pics on Manner's site that show that, or if the Gen 2 calls out a different torque spec.

 

[NavyshooterM40]

Appreciate it. Yeah I’ve heard the Ultimatum can cause issues, good to know the MPA works well with it.

The JP Enterprise APAC works great with the Ultimatum

 

[M338]

Is that the Gen 2 MCS-DBM Mini Chassis? I'm struggling to find pics on Manner's site that show that, or if the Gen 2 calls out a different torque spec.

Yes it’s the gen2

 

[SmokyJoe]

I know my krg doesnt as I had it out recently enough to fresh memories, not sure of the mdt or xlrs, never paid attention to it.

The XLR Element 3.0 is 65/65 ftlbs; rear tang is well supported. This chassis matches well to the Fuzion action...lots of solid contact from front to rear.