Pressure Signs?

[03psd]

Can someone please take a look at these primers / headstamp and give me an opinion on possible pressure issues, please.

Load is 38.7 gr of 10x with 300gr Sierra Game King fired out of my .375 Raptor SBR. 38.5gr is the suggested starting charge with 40.5gr being the max charge. Bolt is dual ejectors and seemed to cycle fine although brass ejection location was inconsistent.

 

[03psd]

Pic added

 

[CJS-6.5]

I would back it down if mine looked like that. What's jump or jam?

 

[Evintos]

Pic added

I'd back off. Those bent rim/extractor marks look nasty and ejector marks are the signs of high pressure. If you have an adjustable gas block, you can try slowing down the unlock timing by reducing gas flow or increasing the buffer weight, which may help.

 

[03psd]

I'd back off. Those bent rim/extractor marks look nasty and ejector marks are the signs of high pressure. If you have an adjustable gas block, you can try slowing down the unlock timing by reducing gas flow or increasing the buffer weight, which may help.

View attachment 6963424

I do have an superlative arms adjustable gas block so I can slow down the gas. It’s pretty much wide open right now. These cases are from my inaugural range trip with this trifle so there is definite tuning needed.

 

[spife7980]

You have virtually every pressure indicator there is short of your gun exploding.

 

[03psd]

You have virtually every pressure indicator there is short of your gun exploding.

Well thank goodness I wasnt batting 1.000 that day!
Considering I was at the starting point of the published load data and encountered the above pictured issues. By how much would it be advisable to reduce? 2.0gr?
Below is load data from 375Raptor DOT com

Sierra 300 Grain Game King – 2.715 inches COAL
Powder: Alliant Reloader 10X

• Primer: CCI 250
• Brass: Starline 308 Winchester – 1st Firing
• Starting Load: 38.5 Grains
• Maximum Load: 40.5 Grains
• 2250 fps with 20-inch barrel

 

[Howland]

The cratered primers and ejector marks are reasons to step down the powder charge. The rims are a reason to restrict gas flow. I'm thinking that damage is done before your buffer tube comes into play.

I had one brand of ammo that the piece of rim sheared right off it was so overgassed with no other signs of pressure. Until I throw an adjustable gas block on it, I have ten boxes that make pretty cool paperweights. If I hadn't had a cleaning rod with me, it would have been a very brief range session. Later while swapping out the trigger, a little piece of that rim tumbled out of the trigger housing. That could also have shut me down.

 

[bax]

Well thank goodness I wasnt batting 1.000 that day!
Considering I was at the starting point of the published load data and encountered the above pictured issues. By how much would it be advisable to reduce? 2.0gr?
Below is load data from 375Raptor DOT com

Sierra 300 Grain Game King – 2.715 inches COAL
Powder: Alliant Reloader 10X

• Primer: CCI 250
• Brass: Starline 308 Winchester – 1st Firing
• Starting Load: 38.5 Grains
• Maximum Load: 40.5 Grains
• 2250 fps with 20-inch barrel

Something is not right here. You did your part. You read the book and started at the low end of the range but you got results more like the top end. You should try to figure out why it is doing this. For example, you might chrono the bullets and see what kind of velocities you are getting. For example, if you are getting low end velocities but high end pressure signs, that points to soft brass. On the other hand if you are getting high-end velocities and high-end pressure signs then that load data does not match up with your gun. According to the Alliant site 10X is for "Light varmint/light bullet loads". Maybe I am wrong but I'm thinking that 300 grain bullets in a 375 is not "Light varmint/light bullet loads". I have a 375 H&H and when I put 300 grain bullets in that case, I use a lot of slow-burning powder. On the 375raptor.com site I see 10x loads all over the place but its your face 3 inches from the chamber. You should do what you think is best but if I was in your place, I would back off until I figured this out.

 

[spife7980]

I, personally, would drop down a grain since you know what you’re at right now doesn’t detonate, crank that gas closed and shoot 10 incrementally opening the gas one click at a time until the bolt locks back. Watch for those pressure signs and if they are still nasty with the gas closed then you need to drop further or evaluate what you’re doing so far as jamming bullets, powder choice, crimping whatever. Actually you should be doing that throughout the entire process but you know what I mean.

 

[Evintos]

Well thank goodness I wasnt batting 1.000 that day!
Considering I was at the starting point of the published load data and encountered the above pictured issues. By how much would it be advisable to reduce? 2.0gr?

The gas adjustment will correct some of the mangled case rim/bent rim issues as well as the ejection pattern issue. What's your current reloading setup and process? Calibrated scale? Powder measure throwing accurately? Reducing a couple of grains may solve the issue of the over pressure (ejector marks, cratered primer). RL-10X if I remember correctly is really temp sensitive so you may need to go reduce even further than 2.0gr depending on temp.

 

[CJS-6.5]

I only asked about jump or jam because I was concerned that your gun was not setup correctly. Just trying to figure out why you were about to blow up with that charge weight. Can you find out the reamer dimensions and what all happened during the build?

 

[FLIGHT762]

Like everyone suggests, back off on the powder slightly and turn the gas system off and slowly open it, firing one round at a time from the magazine until you get the bolt to lock back. I do that on all of my adjustable gas block rifles. See what the cases look like after that.

 

[03psd]

Thanks all. Just looking for a little clarity. Would backing off 2.0 gr and figuring out minimum operating gas be a good start and only they begin to increase powder charge in .2gr increments looking for pressure signs? I’m trying to avoid having multiple variables changing at the same time.

 

[CJS-6.5]

Are you loading to Sammy spec or mag length? And what primer?

 

[CJS-6.5]

Sorry just saw Cci 250.

 

[CJS-6.5]

What buffer spring?

 

[03psd]

I only asked about jump or jam because I was concerned that your gun was not setup correctly. Just trying to figure out why you were about to blow up with that charge weight. Can you find out the reamer dimensions and what all happened during the build?

It’s an X-Caliber barrel chambered using Arne Brennan’s dimensions for the cartridge. I don’t have the specs in front of me but they are listed supplier (1 of 2) for the cartridge.
I’ll see what I can find.
Powder charges were individually weighed using a RCBS electronic scale calibrated before use.

 

[03psd]

What buffer spring?

Tubb flat wire AR10

 

[CJS-6.5]

It’s an X-Caliber barrel chambered using Arne Brennan’s dimensions for the cartridge. I don’t have the specs in front of me but they are listed supplier (1 of 2) for the cartridge.
I’ll see what I can find.
Powder charges were individually weighed using a RCBS electronic scale calibrated before use.

I would call xcaliber at once. This isn't the first problem...often dreamers are old, and threats are cut wrong, not to speak of wrong twists..

 

[CJS-6.5]

There is a reason they have the shortest wait times.

 

[03psd]

Sorry just saw Cci 250.

Actually I am using standard CCI 200 primers. I didn’t pick up on that in the load data. 250’s woukd have made my problem even worse, no?

 

[03psd]

There is a reason they have the shortest wait times.

I waited just over 14 weeks . In the morning I will dig out my order sheet and the spec sheet that came with the barrel.

 

[CJS-6.5]

I waited just over 14 weeks . In the morning I will dig out my order sheet and the spec sheet that came with the barrel.

Holy cow! It took that long to screw it up?

 

[CJS-6.5]

I'm actually trying to get someone from the Kalispell factory to chime in but I doubt they will because management has bet crap for so long that they are selling cheap just to get a break in between breaks.

 

[spaniel]

Without velocities it's tough to completely diagnose. Did you measure the distance to the lands to verify you aren't jamming the bullets? That would increase the pressure. If you are using book minimum loads, you should see book minimum velocity. It really helps if you know whether you are running book minimum loads and getting minimum velocity with pressure issues, or abnormally high velocities which would at least line up with having a pressure issue.

 

[Evintos]

Thanks all. Just looking for a little clarity. Would backing off 2.0 gr and figuring out minimum operating gas be a good start and only they begin to increase powder charge in .2gr increments looking for pressure signs? I’m trying to avoid having multiple variables changing at the same time.

Yes but do this after you verify that the barrel is made to correct specs. When the AGB is adjusted properly, the excessive pressure signs will be - the bent rim/extractor marks won't be as severe, light ejector marks, minor flattening of primer/cratering. If you start seeing any one of those, stop, or accept the risk of pushing limits.

Here's an example pic of one round reaching overpressure limits but with a properly adjusted gas block (from my 308 AR).

 

[03psd]

How exactly do I verify the barrel was made to proper specs? It’s the proper length, mounted properly, the twist looks correct at 1:10 (but I don’t have a precise way to verify this). Rounds chamber without issue. Rifling looks clean and well done but again I am not a gunsmith, machinist, or barrel maker so I’m not sure how I am supposed to verify.
For what it’s worth I was pleased with the groups it shot at 50 yards during this outing despite the pressure signs. Groups were ~1” .

 

[03psd]

Are you loading to Sammy spec or mag length? And what primer?

I don’t believe there is a SAMMI spec since this is a wildcat but I did load to the prescribed length in the load data, 2.715”. This is shorter than mag length of 2.810”

 

[Evintos]

How exactly do I verify the barrel was made to proper specs? It’s the proper length, mounted properly, the twist looks correct at 1:10 (but I don’t have a precise way to verify this). Rounds chamber without issue. Rifling looks clean and well done but again I am not a gunsmith, machinist, or barrel maker so I’m not sure how I am supposed to verify.
For what it’s worth I was pleased with the groups it shot at 50 yards during this outing despite the pressure signs. Groups were ~1” .

You'd need 2 headspace gauges (375 Raptor headspace gauge set). Assuming it headspaces correctly, the next thing you'd check is the amount of free bore (mentioned by @CJS-6.5 regarding jump/jam). Make sure your trim length (1.865 after sizing) is correct and your COAL (2.800) is correct. Create a dummy round (no powder or primer), use a sharpie and color the bullet. Chamber the round, see where bullet makes contacts with the lands of the rifling. Also measure the COAL after chambering to see if you're getting bullet setback. Post a pic.

Not enough freebore will give you excessive pressure (people call it tight chamber but I believe the proper term is short chambered) and can't be rectified except for recutting the throat area or shooting until natural throat erosion somewhat increases the free bore. The problem with a short chambered barrel is if you ever decide to try the other loads with COAL 2.800, you'd have to start way below published starting loads. Example:

Sierra 350 Grain Match King – 2.800 inches COAL

Powder: Accurate Arms 1680

• Primer: CCI 250
• Brass: Winchester 308 Winchester Commercial – 1st Firing
• Starting Load: 30.0 Grains would be way too high, would probably need to start at 25.0gr
• Maximum Load: 33.0 Grains
• 1825 fps with 18 inch barrel and 1725 fps with 10.75 inch barrel.

 

[03psd]

You'd need 2 headspace gauges (375 Raptor headspace gauge set). Assuming it headspaces correctly, the next thing you'd check is the amount of free bore (mentioned by @CJS-6.5 regarding jump/jam). Make sure your trim length (1.865 after sizing) is correct and your COAL (2.800) is correct. Create a dummy round (no powder or primer), use a sharpie and color the bullet. Chamber the round, see where bullet makes contacts with the lands of the rifling. Also measure the COAL after chambering to see if you're getting bullet setback. Post a pic.

Not enough freebore will give you excessive pressure (people call it tight chamber but I believe the proper term is short chambered) and can't be rectified except for recutting the throat area or shooting until natural throat erosion somewhat increases the free bore. The problem with a short chambered barrel is if you ever decide to try the other loads with COAL 2.800, you'd have to start way below published starting loads. Example:

Thanks. Barrel was supposedly headspaced with the bolt that came with it. I totally forgot about that bolt and used a different new BCG so that may be part of the issue, thats my mistake. I will mock up a dummy round to check the throat and report back with a pic.

 

[03psd]

Barrel work order

 

[03psd]

Damn this is frustrating!!!! I spent a little time today mocking up some rounds to the same length and tried chambering them. Either the bolt wouldnt fully close or it would not allow me to eject the case without mortaring the charging handle. I am guessing the bullets are "jammed" into the rifling which is both causing my pressure issues as well as the trouble extracting unfired or dummy rounds. What is the fix for this? is more research worthwhile such as deeper seating depths? although this seems a crappy way to get around a short chamber, if thats the problem. Unfortunetly only a couple people make loaded ammo and they are perpetually out of stock so I cant eliminate my hand loads as part or all of the issue. I am using CH4D dies and a Giraud power trimmer so its quality stuff. I hate to spend another $120 on guages to find out what it seems others here have already determined, ie the barrel is a POS, but I will if theres a possiblity of some other outcome. I have a bunch of money sunk into this experiment. I am wondering if I should have just gone with a .458 SOCOM or other, more mainstream, big bore. Frustrating......

 

[CJS-6.5]

Personally I would just seat them deeper until the issue goes away.

 

[spife7980]

When you chamber the round; do you see imprints of the lands on the bullet? You can also color the bullet in sharpie or smoke it over a candle (obviously no powder or primers present)

Using Over All Length (OAL) is alright, thats close but the bullet tips vary, some times wildly.
CBTO is the Case Base to Ogive Length (the curve of the bullet) is more consistent.
http://www.bergerbullets.com/effects-of-cartridge-over-all-length-coal-and-cartridge-base-to-ogive-cbto-part-2/

To measure off the ogive you want a bullet comparator, this will give you a more consistent point to measure the bullet with.
https://www.brownells.com/reloading...ad-bullet-comparator-basic-set-prod35659.aspx

There are a couple way to actually measure the relative length of your chamber.



1 slit the neck of a case so that it is only holding on to the bullet with enough force to keep it in the case but so that it slides easily into it when pressed. Chamber it and measure the length that the bullet slid into the neck. http://www.larrywillis.com/OAL.html

2 the same way but instead close the bolt on an empty chamber. Insert a cleaning rod down the barrel and push it up against the bolt face, mark that point on the rod (carefully, its a precise measurement we are after here). Then chamber a round with the bullet in it and close the bolt (loose neck tension can help here too since you can already attest to it being a bitch to jam the bullet too deep). Insert the cleaning rod and mark its new length on the rod. The difference between the empty and loaded chambers should be your max over all length.
Sinclar makes some little stops that make this easier https://www.sinclairintl.com/reload...lair-bullet-seating-depth-tool-prod35491.aspx

3 Hornady makes a tool to do this as well. Push a case gauge and chamber it then push the bullet through it until you feel it contact the lands. Once you have that you can mesure its OAL or better yet its CBTO with the bullet comparators.
https://www.brownells.com/reloading...ating-depth-tools/length-gauge-prod70272.aspx

4 The wheeler method is what I like but its not so easy for savages and ars since you dont have the nice bolt handle to use.

 

[Evintos]

Damn this is frustrating!!!! I spent a little time today mocking up some rounds to the same length and tried chambering them. Either the bolt wouldnt fully close or it would not allow me to eject the case without mortaring the charging handle. I am guessing the bullets are "jammed" into the rifling which is both causing my pressure issues as well as the trouble extracting unfired or dummy rounds. What is the fix for this? is more research worthwhile such as deeper seating depths? although this seems a crappy way to get around a short chamber, if thats the problem. Unfortunetly only a couple people make loaded ammo and they are perpetually out of stock so I cant eliminate my hand loads as part or all of the issue. I am using CH4D dies and a Giraud power trimmer so its quality stuff. I hate to spend another $120 on guages to find out what it seems others here have already determined, ie the barrel is a POS, but I will if theres a possiblity of some other outcome. I have a bunch of money sunk into this experiment. I am wondering if I should have just gone with a .458 SOCOM or other, more mainstream, big bore. Frustrating......

Is this is with the headspaced bolt that came with the barrel? I forgot to mention another test to do is to put a properly sized empty case (no bullet, powder, primer) and see if it'll chamber. If it chambers, your head space is probably correct in which case..

Unfortunately if they're jammed to the point of feeding issues with the 2.715 COAL dummies, it's ridiculously short chambered and I would demand the manufacturer refund your money in full or recut the chamber/throat properly. I wouldn't even bother with the barrel since you wouldn't even be able to chamber the 2.800 COAL spec loads.

If they're jammed with 2.800 COAL dummies, you may be able to salvage it by experiment. You can mock up some dummies to see at what COAL they will start chambering reliably. If you decide to seat deeper, depending on how deep, you may want to back off the load by as much as 5.0 grs if not more (starting around the low 30.0gr range).

If you really want to experiment - It's possible it was cut on the short end but will reliably feed the 260gr Nosler Load with a 2.685 COAL or the Sierra GameKing 250gr 2.690 COAL. Would require you to buy those bullets.

Side note: more gauges and tools are almost always useful in handloading, imo.

 

[03psd]

This is insane. I chambered an empty piece of brass without issue. Went in easy and came out easy when I raised the muzzle up. I then tired a piece of the same brass with just a bullet seated and it got stuck so I had to use a cleaning rod to tap it out from the muzzle end. I then started seating it deeper and deeper to see at what length it would chamber fully and still come back out without needing to be shoved backwards. I got to 2.565" COAL and it was still getting stuck. At this point I actually think the ogive was inside the neck of the case - OBVIOUSLY too deep. Unless someone has a better idea I think I need to call X-Caliber tomorrow and arrange for them to take a look at this barrel and address the issues. The purpose of this upper was for 300 and 350gr bullets (some supressed) so I am not really interested in being limited to 265gr pills.

 

[CJS-6.5]

Not unusual for that company. At least they got the caliber right.

 

[03psd]

Not unusual for that company. At least they got the caliber right.

Ok, whats the back story here.? Its clear you have an opinion regarding X-caliber. I am not real happy with them at this moment either. Care to share any first hand knowledge or experience? I was aware of some turnover in personnel as that was the reason given for my long lead time. I double checked my dates and my wait was almost 20 weeks. That and a broken reamer supposedly.

 

[hlee]

So, I'm going to throw my 2 cents into this mix. I've got a 6.5 Grendel that I'm working a new load for. As s control, I'm using some hornady match ammo. On my initial range session there wee no pressure signs on the control ammunition. My hand loads, however wee it fully cycling the action. When I got home I changed the spring in my SCS to the light weight one and opened up the gas block to Full open. My control cases now have flattened and cratered primers. I expect that dialing the gas back down will eliminate the signs of pressure.

Something that I read when I started reloading for gas guns was that if the gas settings are not correct, you can get pressure signs without high pressure. These signs are indications of pressure, but they can be false signs. This is not to say that one should ignore the signs, but it is even more important to understand the underlying causes in semi autos. Reloading for gas guns is grad level reloading...

Edit- I posted before reading far enough to see that you have a pretty fair diagnosis of your issue. Disregard if this is not of use.

 

[Evintos]

I got to 2.565" COAL and it was still getting stuck. At this point I actually think the ogive was inside the neck of the case - OBVIOUSLY too deep. Unless someone has a better idea I think I need to call X-Caliber tomorrow and arrange for them to take a look at this barrel and address the issues. The purpose of this upper was for 300 and 350gr bullets (some supressed) so I am not really interested in being limited to 265gr pills.

At 2.565 COAL, I highly doubt the 260gr would work. If they give you any trouble about fixing the problem, returning the barrel or refunding your money, remind them that you waited 20 weeks for a barrel that could've seriously harmed you...

 

[CJS-6.5]

Ok, whats the back story here.? Its clear you have an opinion regarding X-caliber. I am not real happy with them at this moment either. Care to share any first hand knowledge or experience? I was aware of some turnover in personnel as that was the reason given for my long lead time. I double checked my dates and my wait was almost 20 weeks. That and a broken reamer supposedly.

I was looking for a couple prefits a while back, they had good prices so I started researching them. There was a lot of unhappy campers with stories like yours. Wrong twist rates, wrong freebore, muzzle not threaded as specified...Google it. You will find it.

 

[Evintos]

@03psd Here's something I thought you would find interesting. http://www.snipershide.com/shooting/threads/x-caliber-barrels.6536161/post-6549830

I purchased a 375 Raptor barrel from X-Caliber (LR 308 project), along with a X-Terminator muzzle break. Unfortunately, the barrel they sent me had no freebore, a condition they blamed on a defective reamer. X-Caliber believed they had tracked down all of the "freebore free" barrels prior to leaving their shop. Nope. And on top of that, I had ordered 5R rifling, but the same chamber cast that revealed the freebore issue also displayed traditional 6 land and groove rifling. I've read that the shop is experiencing some turnover of a few key people. If that's true, that could explain the lack of quality control concerning the barrel they shipped me. I have no doubts that they're capable of producing a quality product at a reasonable price, but given that I have to wait another 10-12 weeks for a new barrel due to their negligence, I'm not real happy with X-Caliber at the moment.

 

[03psd]

@03psd Here's something I thought you would find interesting. http://www.snipershide.com/shooting/threads/x-caliber-barrels.6536161/post-6549830

Yup. I found that earlier and posted in it. I sent the OP a PM but I don’t really expect a response as he hasn’t logged in here since December 2017. Hopefully he does. Thanks

 

[03psd]

OK, so I called X-Caliber this morning and spoke to Pat. As I described the issues, he seemed to know exactly what I was talking about as if I wasnt the first time he had heard of this. He almost immediately offered to have a return authorization sent so they could figure it out. I pressed him about the issue and he said a number of barrels had left the factory after only being "rough reamed" and that they never got "finished reamed". Not being a gunsmith I dont know what this means or if its plausible or an over simplifacation designed to just shut me up. Whatever it is, it sounds bad. If I get the authorization today as promised I will ship the barrel back tomorrow. I have already disassembled the upper. I know any company can make mistakes since they all employ humans. The test will be how they respond and treat customers once they are aware of the problem. I will update this thread as I have news. stay tuned.

 

[bax]

You figured it out. You didn't blow up the gun or hurt yourself. Consider it good education. If they fix it then you lost some time so what - worse things will happen to you. Write down your diagnosis procedure, you should check every new weapon and barrel using about the same steps. If you pull and replace a barrel, you should do the quick version just to make sure. Changing the bolt was not a good thing but you got that.

FWIW, I have a $1000 barrel where the lands are .180 longer than SAAMI. I wouldn't let those people touch that barrel again no matter what. Reputations can go both ways.

 

[03psd]

Barrel is on its way back to X-Caliber for inspection and one form of correction or another to be determined.

 

[jafo96]

Barrel is on its way back to X-Caliber for inspection and one form of correction or another to be determined.

Any update on the progress of your 375 Raptor?