Reply With QuoteDefinitely building pressure for some reason. How long did you wait between shots. On occasion, a hot chamber will affect the "hotness" of a load.
Took my new-to-me 110 out today to get sighted in before deer season begins on Saturday. The good news is that rifle, 1999 vintage in .270 with no noticeable wear and tear, put the first 4 Federal Powershock 150's into a nice clover. Then the trouble began. I closed the bolt on the 5th round normally, fired, and then had a hard time rotating the bolt to extract the shell. The bolt eventually opened up with a little elbow grease and retracted, but the shell stayed in the chamber. I tapped it out using a dowel and noticed some powder marks on the rim and an indentation from what I believe was the extractor. I looked at the bolt head and everything looked to be in place.
I figured it was a random bit of bad luck so I chambered another (all of these were loaded one at a time through the blind mag) and fired. Again, the bolt was really difficult to rotate and the shell stayed in place, this time with the primer cap angled out. At that point, I put away the 150s and grabbed a 130, hoping it was just the ammo. I fired the 130 and low and behold the same thing happened (this time I lost the primer) and upon removing the bolt, I noticed my extractor was gone. I was able to find a spring and the ball bearing, but not the extractor itself.
I've attached a pic and you can see the cases from left to right (1st to 7th round shot). Is this an extractor issue or do I have a headspace problem? I bought the rifle used and, while it didn't see a lot of use, it definitely has a few rounds through it. There don't seem to be an bubba modifications or anything out of the ordinary....doesn't Savage check the headspace? At no point did I see any indications on the extractor itself that something was wrong.
Any ideas on how to solve this? Has anyone seen this before? My only mod is a new SSS Comp. Trigger which is fantastic.
Thanks for the help.
Matt
[img width=600 height=450]http://img841.imageshack.us/img841/6502/img4882.jpg[/img]
[img width=600 height=450]http://img696.imageshack.us/img696/7108/img4884d.jpg[/img]
Definitely building pressure for some reason. How long did you wait between shots. On occasion, a hot chamber will affect the "hotness" of a load.
At least a minute between shots. Any possibility I could close the bolt without the extractor going around the rim? Wouldn't that leave a gap between the bolt face and the cartridge base that could cause the primer to become unseated and the pressure marks?Originally Posted by lostart
Just grasping at ideas here.....
I'm not an expert, nor do I play one on TV, but I see pressure.
You said "new to me". Something looks way wrong. Headspace? Is it factory ammo? Any recalls on the ammo?
A pro needs to figure out how to prevent you from having a Kaboom.
Blown primers with hard bolt handle lift usually indicate pressure problems but in my experiences they are cratered and really flattened. Wondering about headspace which you could roughly check. Use a cartridge and put a layer of tape on the cartridge base, chamber and close the bolt. If bolt closes then add another layer of tape. Continue checking in this manner until the bolt will not close. Should be able to get one layer of tape maybe more dependant upon tape thickness. Do a search on this site as its been explained in prior posts. Another possibility is the barrel is really copper fouled and needs good cleaning too remove copper deposits.
Odd how the problem is progressive.
Did you check the barrel and nut to see if its tight? Almost like its working loose as you go.
Build up in the chamber throat? Carbon or copper. ?????
Stu
The barrel nut is still tight. The throat is pretty dirty now, so I'll clean it up tonight and have another look.
Yes, I bought the gun used about 10 days ago from a 'reputable' gun shop. The bore was bright and shiny when I got it, so I inferred a pretty low round count.
Yes, factory ammo....don't reload yet.
Matt
This does not look like a headspace problem. The cases do not show any bright, shiny rings at the web location. It is a pressure problem. Could be bad ammo, or could be carbon in the throat. Scrub the throat with a brush and acetone to cut the carbon and try it again (once you replace the extractor).
That's a relief. I'll scrub it out tonight. Should I just pick up another extractor from midway? The only reason I was worried about the headspace was that the bolt closed easily when the shells were loaded. If the throat was fouled up, wouldn't it have been difficult to close?
The ammo was purchased new this week.
Matt
A little excessive head space doesn't blow out primers like that. It might push them back and then when the pressure builds it slams the case back against the bolt so the primer re-seats and gets very flat. You show all the indications of a pressure problem.
I agree with you Dirk. I'd be scrubbing the gap space and the first inch of so of the bore with acetone, acetone-ATF mix, Seafoam, Iosso or GM T.E.C. especially since its a used '99 vintage rifle. More than likely it never had the chamber cleaned and might be the very reason it was on the used rack.
Since the problem PROGRESSIVELY got worse with subsequent shots it has every indication of a carbon buildup.
Bill
10-4 on the Acetone/ATF.
What was the temp that day? were the shells out in the sun? I know its been over 100deg around here for the last three weeks and I can guarantee that If i left my ammo in the sun for just a few minutes it would show pressure problems. Just a thought, Hope you get it figured out.
Steve
If that ammo has rode around in a glove box in the south here for only a short time, you have a recipe for problems. The heat causes problems with the powder, plus the vibration of riding it around could cause the powder to granulate. That with the heat = overpressure. Just experienced some cartridges of a friend flattening the primers, wouldn't hit the side of a barn in his 270. They had rode in his truck a couple summers. Got a fresh box, no problems.
The temperature's been cool in the land of fruits and nuts these days. ;D We're only seeing highs up in the mid-70s, low 80s. I can definitely see how serious heat could do some damage.
I dont think 70s or 80s would cause the problem, I would clean it good and try again.
Steve
I say its a dirty barrel and or a carbon ring.
Definitely a cumulative effect.
Probably more a carbon ring.
I would bet that 95% of hunters never clean the chamber.
I know my dads rifles (he is 89 YO now) were in dire need of cleaning.
Some had not been cleaned in many years.
So bad his 243 auto locked up with gunk.
Just because the barrel looked shiney does not mean it does not have multiple layers
of carbon and copper built up. One pass cleaning it wont do it if it was never cleaned at all.
I am no expert, but this is what I would do.
I would use wipeout multiple times on the barrel until the patches no longer come out blue,
plug the end of the barrel, stand it on end and fill up the barrel and chamber with carburetor cleaner and let it sit for an hour.
You probably want to take it out of the stock and probably remove the scope before you do this.
Clean it with brake cleaner.
Hit it one last time with wipe out for good measure and clean the barrel and chamber with brake cleaner
one more time.
Nasty stuff but it gets the barrel really clean.
Then a very light oil patch followed by a dry patch.
All that should get rid of all the copper and carbon.
Check the head space just to be on the safe side and shoot it.
looking at the photos, the primers look to have a sealer painted on them...is that normal for Federal ammo? Just wondering if somehow got some reloads that were in a factory box.
I had the same thing happen on my new FP10 in .223 about 2 months back while out on a p-dog shoot.
Gun bore/chamber was perfectly clean.
My own loads and it blew the extractor off the bolt face like yours.
After I got home and had a close inspection I determined it was that 1 case that was to long in length.
The primer pocket was the same, everything blew out the rear.
It did not happen in a progressive manner. I chambered a round and it went in smooth, but I recall the bolt was just a tad tight when closing it, but not to tight or forced to close.
I shot and had a heck of a time opening it up in the field, saw my bolt face looked odd, the case fell out when I tipped the gun up and tapped it on its butt a few times, thats when I realized the extractor & guts were missing.
I got a new ball, spring & 2 new extractors (1 backup) at my local gun shop for about $3 total. The ball is just a 1/8" steel bearing.
Put it all back and have had no issues since.
I also have a FP10 I got new in the 80s and never had this happen on that one, same loads, brass, tightish closing bolt and no blowouts.
Usually if the bolt closes tight I remove that case, but didnt that time around..
That's how they came from the factory...both the 150s and 130s. No reloads yet. Hopefully soon.
primer sealer-- I think that is pretty normal for federal. I have .223 ammo with both blue and a darker red around the primers.
Hard carbon fouling......you won't see it looking through the bore with a flashlight.
Gonna have to scrub the poo outta that bad boy. It's not in the chamber. It's just forward of the chamber in the freebore or in the first portion of the rifling. As that bullet is released from the case, it hits that constriction caused by the carbon ring and pressures hit the roof. Pressure has only one way to go and Poooof, brass case gets an arse whoopin'.
A light cleaning of the barrel might remove a little bit of it but as you saw, just a few rounds will cause havoc. That would explain your progressive increase in pressure.
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