I don't remember what he said headspace is, but it's chambered tight. He used Lapua Super Long Range yesterday, but the rifle shoots every ammo well.
New CZ 457 24" 1.180 Match Barrel from L3i
- Thread starter Mark_Dorman
- Start date
Headspace.043”Terrific targetcongratulations please share headspace an ammo
Ammo non lot tested Lapua Super Long Range
Every day I get hopeful my barrel shipping notice will be in my email.
On that BR target, targets 14 and 19 will make you say “oh shit” out loud, and give you a little pucker factor. 
There's a batch in lapping right now! Not sure when you ordered but at least things are right on schedule in the shop!
No it is not. We have a rolling order so we will be receiving batches every few weeks starting in three weeks until the entire order is filled. Lead times will start dropping pretty quickly when they start rolling in. We do all the inspections, laser marking, and packaging internally.
Obvious post coming. But I thought someone may benefit from it, so here goes.
My 457 sat in an XLR chassis for a few months while I waited on my manners. I knew that the barrel contacted the chassis for an inch or so, then it free floated the rest of the way. Accuracy was impressive, so I said - if it ain’t broke, don’t try to fix it.
Fast forward to when my manners arrived, I had to open the barrel channel. Using the aluminum tube and sandpaper, I fit the barrel roughly the same way as my XRS. Again- accuracy was great, so I was happy.
My PDC custom chassis arrived this week. I ordered it in September, and it was to be set aside for another build - but I decided to see how it liked my current action. This chassis free floats the barrel completely. At the range today, my zero was off…. By 2 mils at 100 yards. “Well, duh!” - right? It was low now that the chassis was not pushing on it.
Was it coincidence that I shot my best groups at 215 yards with it today? Maybe. Maybe not. This is the chrono results from the second best ammo I shot today. I had a 3-5mph breeze coming from 10:30. At that distance, I just look at vertical spread. Here are a couple of 10 round groups that I shot.
My 457 sat in an XLR chassis for a few months while I waited on my manners. I knew that the barrel contacted the chassis for an inch or so, then it free floated the rest of the way. Accuracy was impressive, so I said - if it ain’t broke, don’t try to fix it.
Fast forward to when my manners arrived, I had to open the barrel channel. Using the aluminum tube and sandpaper, I fit the barrel roughly the same way as my XRS. Again- accuracy was great, so I was happy.
My PDC custom chassis arrived this week. I ordered it in September, and it was to be set aside for another build - but I decided to see how it liked my current action. This chassis free floats the barrel completely. At the range today, my zero was off…. By 2 mils at 100 yards. “Well, duh!” - right? It was low now that the chassis was not pushing on it.
Was it coincidence that I shot my best groups at 215 yards with it today? Maybe. Maybe not. This is the chrono results from the second best ammo I shot today. I had a 3-5mph breeze coming from 10:30. At that distance, I just look at vertical spread. Here are a couple of 10 round groups that I shot.
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I'm curious what rail you are using there? It looks like it fits over the barrel without modifications. Also curious, it looks pretty thin in the portion over the barrel, and concerns with flex or a hard knock bending it?!
I use a Warne 7757M on my L3i barreled set up. This rail fits without modification and provides good flexibility in ring / mount location.
My barrel has been hammering! Thanks to the L3i team for such an amazing product! I’ve been busy hanging hardware on my gunroom wall. One of the 1st place trophies is from a match today that was full of Vudoo and Rimx rifles. Today was also my best score at a PRS match with a 93/100.
Grey Birch chassis, timney trigger, vortex strike Eagle, arc m-brace mount, and MDT grip. ETA: and obviously an L3i Barrel
This rifle balances exceptionally well. The biggest improvement to my shooting has been getting a rifle that balances on a bag. I don’t have to fight the rifle during the stage.
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I will do you one better, Add a scope and remove bipod!
Attachments
I see your chassis is still on back order. Are you currently shipping 457 chassis? I am interested in a new chassis as the Grey Birch chassis fore end is flimsy.
We will start shipping CZ chassis in 2-3 weeks the inlets are in the anodizing queue right now.
I am picking up barrels today! Laser and QC inspections begin immediately! If you want the chamber updated to the wasp reach out to sales, otherwise it ships with a match chamber.
I noticed you have the MDT grip on your grey birch? I have one coming in today and I was wanting the same grip. Did you get the AR version or just the standard?
If I remember correctly the AR version includes machining for the rear take down pin retention spring. The standard version doesn't have this so either works for our case, but if you want to install the grip on an AR you would need the AR version. So AR version only works on an AR, but either works on a bolt action chassis.
The Wasp Chamber is our new match chamber with a shallower 1.5 degree lead, they will both arrive at the same time. The Wasp chamber has an easier bolt close and is more ideal for PRS/NRL use.
Awesome, sounds good. I also noticed the AR version has a 'tang' so to speak on the top rear of the grip so maybe that eliminates some of the shelf off of the back that the standard one has. I ordered one, so when I get it I will check back in!
Man, I just got the email about the Wasp chamber. I will be using this for PRS 22 but I want the most accurate barrel possible. Does the wasp help with extraction? Why is the Wasp better for PRS than ARA?
It is better for PRS because the easier bolt close does not disturb your sight picture and NPA. We have not seen a significant accuracy difference between either chamber. Wasp chamber also allows for easier extraction of live rounds but makes no difference in extraction of fired cases. Guys having problems with extraction of fired cases should check for excessive headspace as that will cause the unsupported base of the case to over expand and wedge itself in the chamber.
I am curious, how much (in thousandths) would it be to be excessive headspace? Using “Go”gauge of 0.043” and “No-Go” gauge (some at 0.045”, I think one is at 0.046”) as reference and different ammo brands have rim thickness such as Eley and Lapua/SK that are measurably different, what excessive headspace have you experienced that resulted in what you described?
I am truly interested in how little (or a lot) in gap of headspace this can happen.
I have seen sticking cases with as little as .048 headspace, depending on the chambers body dimensions and mouth chamfer. Some rifles can handle it better than others depending on the extraction strength of the particular action and how much extractor relief is cut into the barrel (determines how much contact area the extractor can get on the rim)… lots of factors play into extraction but headspace is an often overlooked factor.
Mine's headspaced at .043 and I have no feeding or extraction issues thru the first 600 rds. Eley, Lapua, SK and Norma...so far zero issues. Bolt closure is snug but not objectionable, and so far it has not been ammo picky...all shoot well, some shoot lights out. Will not extract a live round, so what. Headspace is very easy to set precisely with a few basic tools.
Pacific Tool and Gauge but it will probably take 100 years. Lilja sells a go. Manson has some. Not totally necessary if you take the correct measurements with RF but it does make you feel warm and fuzzy.
I have used digital calipers with depth gauge feature to measure the headspace gap (indirectly, requiring measuring barrel tenon and receiver to bolt face distances and calculating what barrel shims to use (YouTube has videos on this). Ended up with getting a micrometer depth gauge for my tool box for consistent measurements - my own use). 22LR go/no-go gauges can be bought from Amazon, Brownells, Pacific Tool and Gauge, MidwayUSA and other places, depending on how much you want spend.
Most do not worry about go/no-go gauges except for gunsmiths and those that like to check headspace after rifle is fully assembled and/or want to tinker with changing headspace for specific ammo (looking at you Eley…).
Using the digital calipers method and barrel shims works for most people and checking on bolt closing (how easy or hard) with spent shell tends to get you in the right place and far away from excessive (0.048”) headspace gap to worry about.
Forget the go/no go set. Any 6 inch caliper with an Igauge T base adapter clamped on will get precise measurements on the tenon and the bolt face depth. Subtract tenon measurement from bolt face measurement and add appropriate shim to get to .043
No extraction issues. Chamber is designed to deeply engrave the rifling, most guys report not being able to extract a live round with the stock CZ extractors. A $100 set of DPG extractors will work, I don't see the need...if the clock expires just send the shot and eject the empty case.
I might he dating myself but when i started shooting NRL22 matches in 2019, almost all of the custom rifles showing up to matches would not extract live rounds. Our match briefings addressed the procedure for spending the live rounds in the chamber. As time has gone on more and more smiths went away from using true Match chambers with deep engraving, so now new shooters think it is a huge deal when a match chamber does not extract a live cartridge.
Would this also cause the bolt opening to be really stiff? I've noticed on ours the bolt gets hard to open after maybe 100-120 rounds have been fired. My thought was it had something to do with the carbon ring build up, but felt it was odd that it didn't affect the bolt close.
Yeah brass that is over-expanded will cause a harder bolt open as it takes more leverage on the primary extraction.
Desert Precision
I did have live round extraction issues, but then I recently watched Josh do the video on CZ457 upgrades. He reviewed the talon extractors from Desert Precision and I purchased some. After receiving the parts and installing them I have not had a single failure to extract for a live round or a fired round. I would recommend these to anyone shooting a 457 with an aftermarket barrel.
I did have live round extraction issues, but then I recently watched Josh do the video on CZ457 upgrades. He reviewed the talon extractors from Desert Precision and I purchased some. After receiving the parts and installing them I have not had a single failure to extract for a live round or a fired round. I would recommend these to anyone shooting a 457 with an aftermarket barrel.
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Coming from centerfire matches, having a bunch of folks shooting positional stages with rifles that can't be unloaded without firing them seems like a bad idea.
Not sure if that's because I'm ignorant of the nuances of rimfire matches, or because guys who've been around rimfire rifles with benchrest chambers have just gotten used to having to pull the trigger to make their rifles safe.
I started a few years prior. I dislike chambers that won’t allow extraction of live rounds. I’ve seen way too many shooters send their chambered round after time expires without even looking through the scope, one junior shooter at nationals even sent it into the ground ~20’ in front of the line on purpose because that’s what they learned at home. Stern lecture about putting it into the berm and skipping rounds shutting down ranges followed for both them and the parent. There’s also liability for those of us that have been shooting for several years - if we’re used to always being able to extract live rounds, we can get complacent and think we ejected one when it didn’t once we get that shiny new barrel or rifle that doesn’t do it reliably.
The risk isn’t worth the negligible reward. Stoked to hear L3i is going with a more forgiving chamber.
Has been hard to open ever since you have fired the first 100 rounds or does it go away after cleaning and then return?
