Defiance Tenon Dimensions on their Prefit actions

[xr650rRider]

Has anyone here done it yet or am I the first. It would be hard to believe I'm the first. They will look something like this one when I'm done.

That's a spreadsheet I put together and posted on AccurateShooter so yes, I've done it and I know I wasn't the first.

https://forum.accurateshooter.com/threads/defiance-pre-fit-tenon-dimensions.4050776/post-38386427
https://forum.accurateshooter.com/t...ing-print-pdf-out-there.4090841/post-38611274

 

[Longtine88]

That's a spreadsheet I put together and posted on AccurateShooter so yes, I've done it and I know I wasn't the first.

https://forum.accurateshooter.com/threads/defiance-pre-fit-tenon-dimensions.4050776/post-38386427
https://forum.accurateshooter.com/t...ing-print-pdf-out-there.4090841/post-38611274

Yes it is but you did such a good job of it I've used it ever since. Very very handy tool!!!! It has made my life easier for sure.

 

[biednick]

So here is an example of who is wrong. Defiance AntiX SA .480" bolt face for a 22 creedmoor. A friend received a 22 creedmoor prefit from a known manufacturer. I will not say who. The attached below is how I would cut the tenon for the measured action. Notice how Measurement A is 0.004" shorter than the Bolt face measurement. I typically see that these two measurements are generally the same. But this bolt is different. I measured the Overall shaft length of the prefit barrel and it was 0.963". Same measure measurement I measured the actions to front lug. No clearance. Bolt will not close. So now I have to fix his problem on a barrel that was suppose to be good to screw down, torque, go gauged check and shoot. I checked 3 other actions on some SA anti's and those 3's "A" measurement to front bolt lugs were all .967". If this bolt would have been a little longer then the barrel prefit would have worked. Also note the bolt face measurement B is .967" and the toe of bolt is .813" making a recess depth of .154". I generally see this as a .150" measurement. So who's wrong...company A who's receiver it is or Company B who cut the prefit for him? It's not a guarantee prefits work unless the action made is exact or at least set's a tolerance for the instead of calling them 0.001". With the lugs 0.004" longer than the bolt face creates excess protrusion.

View attachment 459949

If I'm understanding your post and drawings correctly it seems obvious the action is wrong here. It lookss like they were either off .004" when indicating a part in or missed a dimension by .004" which caused them to miss downstream dimensions by the same amount. Without knowing their order of operations I can't confidently say what happened, but I can see at least one scenario where missing 1 dimension would lead to the situation you're seeing.

I'd be interested in hearing what Defiance has to say about it. Everyone puts out a lemon now and then, and it sounds like your buddy got one. .004" might as well be a mile in the machining world. I'd be surprised if they consider that acceptable.

 

[khmplus]

So here is an example of who is wrong. Defiance AntiX SA .480" bolt face for a 22 creedmoor. A friend received a 22 creedmoor prefit from a known manufacturer. I will not say who. The attached below is how I would cut the tenon for the measured action. Notice how Measurement A is 0.004" shorter than the Bolt face measurement. I typically see that these two measurements are generally the same. But this bolt is different. I measured the Overall shaft length of the prefit barrel and it was 0.963". Same measure measurement I measured the actions to front lug. No clearance. Bolt will not close. So now I have to fix his problem on a barrel that was suppose to be good to screw down, torque, go gauged check and shoot. I checked 3 other actions on some SA anti's and those 3's "A" measurement to front bolt lugs were all .967". If this bolt would have been a little longer then the barrel prefit would have worked. Also note the bolt face measurement B is .967" and the toe of bolt is .813" making a recess depth of .154". I generally see this as a .150" measurement. So who's wrong...company A who's receiver it is or Company B who cut the prefit for him? It's not a guarantee prefits work unless the action made is exact or at least set's a tolerance for the instead of calling them 0.001". With the lugs 0.004" longer than the bolt face creates excess protrusion.

View attachment 459949

Obvious question is whether you contacted Defiance yet and what they said. That's the first thing I would do if I had a question about dimensions on their action.

 

[wallyj88]

I just completed my first bolt action build on a Defiance Tenacity action. Ordered a pre-fit barrel from a reputable manufacturer. I screwed the barrel on and torqued it to spec with the Defiance action wrench. Was going to use my go and no-go gauges to verify headspace, but the bolt would not close on an empty chamber. I emailed the barrel manufacturer, and got a reply, even though it was a weekend. They told me the last 3 or 4 months they had seen a few Defiance actions out of spec. They did not say in what way they were out. They offered to make it right, and I sent the barrel and action in to them. They turned it around in one day, but I was not given the information on which part or dimension was out of spec. I'll leave the barrel manufacturer's name out of this, as they were very helpful. All is well now, but it was a disappointment.

 

[Longtine88]

I gave the action back to my friend and told him that I'd send it back to them. Haven't heard what he did yet.