Interesting. Recently shot a PRS22 match where I slammed my RimX in an XLR Envy Pro (not bedded) into a small slot on a PRS barricade and my zero shifted 1.2 mils (saw the misses on rest of that stage then went to zero board and rezeroed). I assumed the scope internals shifted but maybe the RimX barrel action shifted in the non-bedded chassis?
Foundation Stocks - people are bedding?
I've seen a few guys saying they fully bedded their Foundation Stock. Anyone care to explain their decision to do this? Peace of mind? Poor mating/accuracy without? I just placed an order for an exodus. I've only shot chassis's and Foundation states their stocks don't require bedding/pillars...www.snipershide.com
its pretty easy to tell if its tied to performance/reliability
hit tf out of the barrel on something and shoot it
my sample of one MPA would shift all over
none of my foundations exhibited a shift
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The "a chassis should not need to be bedded" myth........
- Thread starter Rio Precision Gunworks
- Start date
That doesn't make any sense (to me). Assuming the barrel is torqued in place, how would the barrel shift in the action?
The issue isn't alignment in the barrel to action interface. I don't know what the thread size and pitch are in a Rimx off the top of my head but I'm sure they're substantial. Which, coupled with proper torque, would make for a pretty robust joint. I'm no joint engineer but the thought that the barrel shifted in the action has no basis.
It doesn’t need to make sense to you to be a highly probable reason. The fact remains, threads are the WORST method of maintaining alignment between two objects. Add impacts to either of said objects, and the likelihood of misalignment increases dramatically. What did you torque the barrel to?
I'm not the person you originally responded to but I generally will torque the barrel to the action manufacturers specs. For my CDG action that's 125ftlb.
Again, I don't think this has anything to o with alignment. The tension in the joint is going to keep the barrel from being "misaligned" or moving at all. What do you think the barrel needs to be aligned to?
EDIT: Also to be clear I'm not disagreeing with your assertion that threads are not good features to use for alignment. My argument is that it doesn't matter.
What do I think the barrel needs to be aligned to? Ummm, the reticle, and that absolutely matters.
Maybe some folks stress over it but I'm not aware of anyone who is concerned with barrel to reticle alignment. Generally the reticle is aligned to the POI, thus the POA is aligned to the POI. You torque the barrel on the action and then adjust the optic so that POI = POA. The barrel is not aligned to anything it ends up wherever it ends up.
The important bit in the above poster's scenario is not alignment of the barrel, its that some component somewhere in the system has moved. So some joint somewhere has slipped. I'm arguing the barrel to action interface is immaterial because it's very unlikely the joint there would have slipped. As an example a 1.125 threaded joint tightened to 50 ft-lb (arbitrary) results in a bolt tension force of ~2600 lbs. I'd wager it's more likely something in his optic shifted or in his chassis. Anecdotally, I've wacked my barrel plenty of times in PRS stages and continued to hit targets at distance with no shift in POI.
Yeah, the barrel moved, relative to his reticle.
“Barrel alignment to reticle doesn’t matter.”
It’s literally the only thing that matters. POA IS THE RETICLE. WTF do you think you're aiming with, if not the reticle?
“Barrel alignment to reticle doesn’t matter.”
It’s literally the only thing that matters. POA IS THE RETICLE. WTF do you think you're aiming with, if not the reticle?
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Between the reticle and the barrel there are several joints. Inside the scope, rings, mount/rail etc. Assuming it could only be the barrel moving 1.2mils is silly.
That's not what you said though.
I've been addressing your suggestion that the barrel shifted in the action.
If you have an angular difference of the POA between the reticle and the barrel there will be a linear difference in the POI that will get greater with greater range. Simple geometry, right?
I didn't suggest it was the ONLY possibility, just that a consistent shift in one direction likely isn't a lack of chassis bedding. Do think 1.2mils is a lot?
Which of those other joints suffered the brunt of this barrel impact?
What you're saying is simple geometry yes. However that's not the point I was trying to make at all. My point is that the concern is not aligning the barrel to the reticle. The barrel is torqued on and ends up pointing in some direction. That direction may be influenced by machining tolerances, debris in threaded interface, lubrication in the joint, etc but all that does not matter. Generally the barrel is not made to point in a specific direction (generally speaking). The reticle is what is adjusted and aligned to the POI. Which is related to the barrel direction but not the alignment of the barrel.
It's semantics but I think it's important to be accurate with the language.
I mentioned in an earlier post that I was assuming it was torqued on. Again this is an assumption so I can't claim it as fact in the previous poster's scenario but I'd be willing to be the vast majority of barrels out there are torqued on not just screwed hand tight. Even if it was hand tight, I'd still be skeptical that it would shift 1.2mils. I rarely ever torque suppressors on with tools and just put them on hand tight (direct thread with no mounts). They don't seem to move at all.
I've seen barrel impacts move POI more than a mil. More torque is more insurance against it but it really just comes down to how hard you hit the barrel vs. how tight it is, thread fit, shoulder area, etc.
It's a thing that happens, seen it done, done it myself. It doesn't take much movement over the threaded section to make relatively big shifts at 100yd+.
It's a thing that happens, seen it done, done it myself. It doesn't take much movement over the threaded section to make relatively big shifts at 100yd+.
Barrel specificly impacting the prop? A 1”+threaded joint vs all the other weaker joints in the system? Sure, that must be it.
Where I question it is not whether an impact to the barrel can shift POI but whether it's the barrel moving in the action. There's a lot of other joints in the system that would slip before the barrel moves in the action. That's my assumption anyway I don't have any data to back it up except for anecdotal experience.
Did you miss the part where more barrel torque meant less shift? If it's not the barrel moving, why would barrel torque have an effect?
Yeah, no. Definitely the barrel moving. This was the primary issue back in the days of Barloc and WTO Switchlug. If you couldn't get joint stiffness they weren't robust at all. It lead down a rabbit hole where Ted at ARC basically found that there was no truly safe space. If you hit the barrel hard enough it will shift.
You can also bend barrels easier than a guy thinks... but that's a different redneck party.
That's interesting and definitely changes my perspective. I'd be interested to see some studies performed on something like this. I guess I've never seen any issues because I torque barrels on everytime to 125 ft-lbs per the action manufacturers recommendation. And that manufacturer happens to be ARC. Even a hard hit to a 28" barrel with a 6" suppressor caused no shift in my system.
Just did some tinkering and found a reason why I think I should bed my acc elite. Came to find out that the reason the barrel sits about 1mm closer to the right side of the barrel channel is that when I torque the front action screw, it pulls everything slightly to the right when the rear action screw is torqued in.. So that leaves me to believe that there is induced stress, even though everything works and shoots like it should. Looking into the bedding block there seems to be slightly more material on the left side of the front action screw area. Could the cerakote throw the tolerances off, or maybe there is just slightly too much aluminum on the left side?
Biggest thing now is to find someone to bed it or get the courage to do it myself. The smith who built this for me has never bedded a chassis, only stocks
Biggest thing now is to find someone to bed it or get the courage to do it myself. The smith who built this for me has never bedded a chassis, only stocks
Still tinkering and finding the courage to start bedding but just for fun tried and put a piece of electrical tape ontop of the right side contact point of the chassis and low and behold, the barrel stayed true in the barrel channel even after torquing everything up. Im even considering if shooting the gun like this could cause any harm? I guess if the tape wears out the front action screw will become loose but otherwise I dont see the harm in trying it out. But this got me thinking that maybe removing a slight amount of material from the left side of the chassis contact point would relieve the stress
It won’t hurt nothing to shoot it that way IMO, but I’d always tend toward bedding before material removal
So who here has actually bedded their chassis?
I'm assuming you just skim bed it to take up any minor imperfections in the bedding areas? I can't imagine you'd need to to any "machining" to the bedding area.
I have a three KRG Bravos, two on Tikka T3s and one in a T1x. The two T3s seem to fit almost perfectly and I've never noticed a a zero shift when removing and installing the chassis. The T1x however doesn't fit as nicely and at one stage I'd done a Rokslide drop test and found I was getting a zero shift that was chassis related.
I've not noticed an issue with normal use but perhaps I really should be bedding it.
I'm assuming you just skim bed it to take up any minor imperfections in the bedding areas? I can't imagine you'd need to to any "machining" to the bedding area.
I have a three KRG Bravos, two on Tikka T3s and one in a T1x. The two T3s seem to fit almost perfectly and I've never noticed a a zero shift when removing and installing the chassis. The T1x however doesn't fit as nicely and at one stage I'd done a Rokslide drop test and found I was getting a zero shift that was chassis related.
I've not noticed an issue with normal use but perhaps I really should be bedding it.
I bedded my Matrix Pro to try and get this 22GT to shoot - didn’t work 
Thin skin. I roughed up the ano to give it something to adhere to, but that’s all.
I bedded the recoil lug and rear tang on an xlr element Magnesium 3.0 handful of years back. Had a titanium/carbon 30nosler in it, personally believe the recoil was moving the action around a bit inside the chassis, as it shot more consistently once it was bed.
Sorry to keep dragging this out, but you could "see" that or was there drag on the bolt...or ???
Just laying the action in the chassis, there was no contact on the rear tang.
I have bedded many actions in chassis. Some showed improvement some did not. If it shoots well I leave it alone. If it does not have good contact I bed it.
Nothing new Accuracy International started this over thirty years ago when they bonded actions to chassis
Nothing new Accuracy International started this over thirty years ago when they bonded actions to chassis
Spurious relationship. You're picking an over represented chassis manufacturer who goes out of its way to be represented in the PRS to represent all chassis manufacturers.
Then you pick another non chassis manufacturer in the reverse.
Doesn't make it cause and effect. Could mean MPA has a crummy block design. Could mean the top 20 all PREFER to bed their chassis regardless of it being necessary or not.
These articles are a small sample size of nitpicky shooters, all talented, but without verification of any of these rifles performance. Many run multiple rifles and calibers during the season but base the questionnaire answers on the day of the Finale.
Calling it a myth is about equally as silly as saying 'they need bedding'
If you want to do it or think it's necessary, do it. If you don't want to or don't feel it's necessary, don't. I've not had issues getting sub half inch down to quarter inch out of my rifle (depending on barrel, caliber, load) and *gasp* it's in a non bedded chassis.
Must be voodoo magic, or maybe I just didn't buy an MPA. Do what you think will serve you best. This is like arguing about whether or not an 8ball shifter is going to get you extra 50hp on a sports car. If you want one, get it, who cares what somebody else thinks.
Then you pick another non chassis manufacturer in the reverse.
Doesn't make it cause and effect. Could mean MPA has a crummy block design. Could mean the top 20 all PREFER to bed their chassis regardless of it being necessary or not.
These articles are a small sample size of nitpicky shooters, all talented, but without verification of any of these rifles performance. Many run multiple rifles and calibers during the season but base the questionnaire answers on the day of the Finale.
Calling it a myth is about equally as silly as saying 'they need bedding'
If you want to do it or think it's necessary, do it. If you don't want to or don't feel it's necessary, don't. I've not had issues getting sub half inch down to quarter inch out of my rifle (depending on barrel, caliber, load) and *gasp* it's in a non bedded chassis.
Must be voodoo magic, or maybe I just didn't buy an MPA. Do what you think will serve you best. This is like arguing about whether or not an 8ball shifter is going to get you extra 50hp on a sports car. If you want one, get it, who cares what somebody else thinks.
F-class and BR all bed of not glue their actions.
Before anyone says you need special equipment, ammo, skills to extract the difference …yes
But that doesn’t negate that the most accurate rifles in the world are bedded or glued in.
Do what you want, but there is no debate
Before anyone says you need special equipment, ammo, skills to extract the difference …yes
But that doesn’t negate that the most accurate rifles in the world are bedded or glued in.
Do what you want, but there is no debate
+1
Read the responses to this thread...
www.snipershide.com
here's a sample...
Read the responses to this thread...
KRG Whiskey-3: Am I just too perfectionist?
Recently bought a KRG Whiskey-3 Comp pack. First time installing the spigot to the chassis, found the spigot is not super align with the barrel tunnel. Contacted KRG, sent it back, and they fixed it. All good! I can't be more happy with their CS. However, my initial guess on the misalignment...
www.snipershide.com
here's a sample...
That thread is a train wreck not sure how I missed that one LOL!!+1
Read the responses to this thread...
KRG Whiskey-3: Am I just too perfectionist?
Recently bought a KRG Whiskey-3 Comp pack. First time installing the spigot to the chassis, found the spigot is not super align with the barrel tunnel. Contacted KRG, sent it back, and they fixed it. All good! I can't be more happy with their CS. However, my initial guess on the misalignment...
here's a sample...
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