Thanks cattleman99 and EastCoYotes I contacted Bighorn and I think the best option for me is going to be to get the BinNAndy tacsport pro 2 stage that I want, and then send it to them to have it timed
Gunsmithing Bighorn TL3 Stiff Bolt Close
- Thread starter EastCOYotes
- Start date
I have a BnA regular, not the pro model, on an Origin and love it. I'd wait as well.
Also when I tried a few different triggers I called to order cocking pieces to fit to each trigger to give a true heads up test. I forgot who I talked to at Bighorn but he knew what size cocking piece fit what trigger, and when I got them they were all very close, if I remember correctly with about .005 from 0 cock on close
It's a trigger timing issue.
Had the same thing when I briefly owned a TL3 and paired it with a TT. Too much sear engagement. Bolt lift and close was way heavier than it should've been.
Send it to a proper smith for trigger timing services.
*Edit: I see Bighorn took care of it for you, which is great. This reason is why I love the BnA triggers, you can essentially time the trigger yourself.
Had the same thing when I briefly owned a TL3 and paired it with a TT. Too much sear engagement. Bolt lift and close was way heavier than it should've been.
Send it to a proper smith for trigger timing services.
*Edit: I see Bighorn took care of it for you, which is great. This reason is why I love the BnA triggers, you can essentially time the trigger yourself.
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I think I used the following tutorial from BAT machine when I did mine, obviously a little different for a Bighorn but I remember chucking the end of my firing pin into my drill and backing it off that way to remove and change the cocking piece. They've got video links for the removal/disassembly and adjustment
Also remember to take the measurement of your firing pin so when you you back together you know how far to thread it back in.
how i did mine:
take firing pin assy out of bolt
remove TWO set screws in the bottom of the cocking piece. they are super tiny, one on top of the other
grip the spring and loosen the spring/firing pin until it backs all the way out.
remove old cocking piece
insert new
re-install spring/pin. this is the hard part. i have a pair of soft jaws on my vice. i clamp the back of the bolt shroud where the cocking piece sits into the jaws and place something behind the cocking piece so it doesn't move. then i grip the spring and pin with a rag and screw it back in.
re-install set screws with a dab of loc tite.
The way I did mine without tools was to grab a piece of scrap wood and drill a hole the size of the firing pin in it. Then I put the firing pin in the hole and pressed against the wood (firing pin inside the hole) and used the pressure/friction to allow me to change out the cocking piece/shroud. The friction against the wood when compressing the spring was enough to keep it from spinning and allow me to swap out the parts.
I was told by Ray from Bighorn that if you send your trigger in when you place your order for the action they perform the timing for free, if you send it in afterward it'll cost you $50 which is still very reasonable.
I sent mine in. And paid the $50. I also needed the rail trimmed for my barloc to work. They did that for free
To follow up, I called Big Horn and they quickly sent me a call tag and offered to look at my action. When I pulled the rifle out to tear it down I worked the bolt and whatever I was feeling previously was all but gone. I can't explain it but the action went from kind of mediocre feeling in general to very smooth. LRI pretty much nailed it on the first page; there must have been some kind of bur in the firing pin channel that worked itself out.
Yeah Chad really knows his stuff, maybe why he puts out such high quality products. Not to discourage anybody from doing the work themselves but for me it is worth having a professional fix problems like this, they get done right.
I've had zero issues with TT Diamond and Jewell. Just get the TT.
Don't know about the ZCO 5-27 . Have not felt the urge to rush right out to purchase one as it was just released this year. It's never been an issue with any of my Vortex Razor GEN I 5-20x50, or GEN II 4.5-27x56. Frank would be a good source to ask since he did a review on the ZCO 5-27 for Sniper's Hide. However, the appropriate forum for a question in regards to a specific scope and action would have been the Rifle Scopes forum/
I recently bought a Origin. It had .025" cock on close and was a little stiff to run the bolt. I contacted Big Horn and they sent me a U25 cocking piece which fixed the problem. Now it, literally, has 0 cock on close. The bolt now is pretty amazing. It is still a little stiff from it being brand new but in the 100 or so times I have ran the bolt it has continued to get lighter and lighter.
For reference I have a Nucleus and had an Archimedes. The Origin feels better than either of them. The Nucleus' bolt is a little lighter to run but I also have the 15 pound spring installed. The Origin feels better if I install the 25 pound spring to fix the light strike issues. Even though the Nucleus has a lighter bolt throw the Origin feels more robust and solid.
I could never get the Archimedes to work reliably. I tried 7 different triggers, 3 different cocking pieces, but it still had an issue that could not be resolved so I returned it.
For reference I have a Nucleus and had an Archimedes. The Origin feels better than either of them. The Nucleus' bolt is a little lighter to run but I also have the 15 pound spring installed. The Origin feels better if I install the 25 pound spring to fix the light strike issues. Even though the Nucleus has a lighter bolt throw the Origin feels more robust and solid.
I could never get the Archimedes to work reliably. I tried 7 different triggers, 3 different cocking pieces, but it still had an issue that could not be resolved so I returned it.
Hey gang,
After working my way through this thread, I'm at least going to share my measurements with Zermatt/BigHorn and see what they recommend, if they'll send a piece out or if I need to send my stuff in to get timed. I assembled the entire rifle myself with a TriggerTech Primary on the BigHorn Origin. I noticed the lockup of the bolt was really stiff and felt like more than just "new part" stiff. When I asked BigHorn about it they said that it would improve over time, but then I found this thread and did some measurements. I measured the indicator protruding from the back of the bolt as instructed and came up with the following measurements. I took 3 measurements for three different conditions, bolt open (cocked), bolt down locked on an empty chamber, bolt down locked on a round in the chamber. Basically, I got ~0.035" +/- 0.002 inches.
I have not fired a round through the gun yet. I don't know if there's any concern with doing so (potential jam of the cartridge in the chamber or something?). I'll see what BigHorn says, and it was good to get some similar numbers as a few people referenced a CoC of ~0.030". It is kind of tricky to measure since the bolt shroud is not flat in the back.
Does anybody have a link to a video or instruction for the DIY fix?
Any and all comments on my situation are welcome.
After working my way through this thread, I'm at least going to share my measurements with Zermatt/BigHorn and see what they recommend, if they'll send a piece out or if I need to send my stuff in to get timed. I assembled the entire rifle myself with a TriggerTech Primary on the BigHorn Origin. I noticed the lockup of the bolt was really stiff and felt like more than just "new part" stiff. When I asked BigHorn about it they said that it would improve over time, but then I found this thread and did some measurements. I measured the indicator protruding from the back of the bolt as instructed and came up with the following measurements. I took 3 measurements for three different conditions, bolt open (cocked), bolt down locked on an empty chamber, bolt down locked on a round in the chamber. Basically, I got ~0.035" +/- 0.002 inches.
I have not fired a round through the gun yet. I don't know if there's any concern with doing so (potential jam of the cartridge in the chamber or something?). I'll see what BigHorn says, and it was good to get some similar numbers as a few people referenced a CoC of ~0.030". It is kind of tricky to measure since the bolt shroud is not flat in the back.
Does anybody have a link to a video or instruction for the DIY fix?
Any and all comments on my situation are welcome.
I have since bought another Origin action. It is setup identical to the first so it too had some CoC. Called Zermatt and I received the correct one to fix most of it. I did some light sandpaper work so I now have ~.005” fall on close. It felt so much better I went back to the first and duplicated it.
Replacing the cocking piece is super simple. No need to send it in if you don’t want to.
Replacing the cocking piece is super simple. No need to send it in if you don’t want to.
I think this FAQ from BAT Machine is what I followed as the bighorn functions very similar.
I don’t recall using a cordless drill chuck to hold the pin though.
Anyways the gun should still function fine with some cock on close so you could shoot it now, it would still go into full battery as is just maybe not as smooth as you like until after the new cocking piece is installed.
I don’t recall using a cordless drill chuck to hold the pin though.
Anyways the gun should still function fine with some cock on close so you could shoot it now, it would still go into full battery as is just maybe not as smooth as you like until after the new cocking piece is installed.
Update to my issue. I sent pictures to Ray at Zermatt/BigHorn and he made it sound like I had updated stuff, and he sounded surprised by the issue (which surprised me given this thread). When I broke down the rifle to ship him the action and trigger, I noticed the problem went away. Turns out, the front action screw was ~0.020" too long, and slightly interfering with the bolt lugs during lockup. I ground the screw down a little bit, reassembled it, and the bolt operates without any resistance. Hopefully, this information helps someone in the same situation. The action is in a KRG X-Ray Gen 4 Chassis.
Oddly enough, I think I would have discovered the root cause earlier if this thread did not exist, or if the bolt had a more defined interference than what I was experiencing. I'm actually glad I went through the process of disassembling. It seems like a pain, but sometimes taking it all apart and watching out for a specific issue is the way to go.
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