how to use headspace gauge? |
Post Reply | Page 12> |
Author | |
AussieInUtah
Groupie Joined: January 29 2012 Location: United States Status: Offline Points: 32 |
Post Options
Thanks(0)
Posted: June 02 2012 at 1:40pm |
While shooting my Ishapore SMLE No1 MkIII last weekend, I had a case head separation which left the front part of the case stuck in the chamber of my rifle. Not fun. Had to get a gunsmith to fish it out for me. One of the other cases I'd shot that day developed a similar crack, but didn't fully separate.
The case had been reloaded about 4 times, maybe 5. The load was 41.8 gr Varget behind a 174 gr SMK HPBT. I don't think that is an excessively hot load. It gives a muzzle velocity of 2480 fps. The cases are made by Winchester. This is the first time I've had a case head separation in this gun. The gunsmith said that the cases might be getting excessively stretched because I have excessive headspace. So I bought Go and No Go gauges from Forster. Only problem is that the case extractor is catching on the gauge so I can't close the bolt on either of them. What to do? Am I supposed to remove the extractor from the bolt? How do I do that? Should I also get a Field gauge? Are these Forster gauges what I need, or should I be getting a different brand?
|
|
SW28fan
Special Member Donating Member Joined: July 02 2007 Location: Texas Status: Offline Points: 2951 |
Post Options
Thanks(0)
|
You Need to Slip it on the bolt with the rim under the extractor like you were chambering a round from the magazine. Numrich Arms has rather modestly priced 303 Broken She!! extractors.
Sometimes inserting a fresh round into the chamber will catch the broken cases enough so you can extract it.
One question were you Neck Sizing or full length sizing? Neck sized cases hold up much better.
|
|
Have a Nice Day
If already having a nice day please disregard |
|
LE Owner
Senior Member Joined: December 04 2009 Status: Offline Points: 1047 |
Post Options
Thanks(0)
|
I've always heard its best to remove the extractor when using a headspace gauge, and pushing the gauge out with a cleaning rod if necessary. Some prefer to remove the firing pin and spring as well.
You must not force the bolt closed, which is a good reason to remove the firing pin and extractor, since either causes significant back pressure on the bolt when closing. Removing the extractor is easy, just take out the screw and pull the extractor out. Getting it back in can be a problem due to the stout little V spring. I'll see if I can find proper instructions for you. Try this link I'm all for tightening headspace by replacing bolt heads with a higher number, but few #2 and fewer #3 boltheads are out there these days. #1 boltheads are available from several vendors. Also since over long boltheads were sometimes sanded to fit many no longer measure the length indicated by the number. To some extent a bolthead may compress by a few thousandths after many thousands of rounds. A new old stock bolt head of the same number as the bolthead now present may be a few thousandths longer simply because it hasn't been subjected to repeated firings. A new condition bolt body if available might be the answer. These are available for the SMLE (No.1) but I've not seen these listed for the No.4. Bolt bodies require careful hand fitting to insure even locking lug contact. PS If using Seller & Bellot cases those are a problem and are the least durable when reloaded. Many have recommended Privi Partizan as the best case for reloading. To get the most reloads from every case, and the best accuracy as well, I mark case rims and after first firing neck size only then rotate the case 180 degrees when firing for the second time. This insures equal expansion of the case, which will help in presenting the bullet to origin of rifling without cant. I also only size 2/3rd of the neck. The equally expanded unsized rear portion of the neck also insures proper presentation of the bullet. Try this and you may find group sizes are immediately cut in half. Seating bullets out far enough to take up the slack in the distance to OR in the throat also reduces group sizes remarkably. I prefer the 150 gr Hornady .312 bullets. These if seated to the crimping groove give a short OAL. I instead seat these to the full OAL which leaves the crimp groove exposed. You may not need to seat them that far out since some barrels have more or less slack in the throat. You do not want to seat them too far out as this can raise chamber pressure. I don't crimp. The less the pull strength on the bullet the less the effect of variations in pull strength. It depends on how tight the case neck grips the bullet, since you don't want to risk a bullet being pushed deeply into the case, which can cause serious (sometimes disasterous) pressure increase. |
|
AussieInUtah
Groupie Joined: January 29 2012 Location: United States Status: Offline Points: 32 |
Post Options
Thanks(0)
|
I can't slip it onto the bolt with the rim under the extractor. That doesn't work. I'm going to have to remove the extractor. I looked at the instructions that LE Owner pointed me to. They are for a No 4 rifle. I have a No 1 Mk III. Is the procedure the same?
I was using an RCBS neck sizing die. That is one reason why I am unhappy about the short case life in this rifle. Because I have a No 1 Mk III, I can't replace the bolt head to adjust headspace. That only works on No 4 rifles, as far as I am aware. What other options are available?
|
|
Lithgow
Senior Member Joined: October 25 2005 Location: Australia Status: Offline Points: 1417 |
Post Options
Thanks(0)
|
Yep the procedure is the same for both the No1 and No4 bolts.
You can replace the bolthead on the No1 to correct headspace but you will need to have the correct length bolthead. It is handy to have a good selection. Measure the length of the one you have and look around for a longer one.
Since you are using Forster guages you will find that your headspace will most likely be out of spec as mil spec guages are not the same as SAAMI guages.
The correct method is to remove the extractor, the reasoning behind this is that it can damage the headspace guage and raise burrs on the guage which in turn could give fals readings.
|
|
AussieInUtah
Groupie Joined: January 29 2012 Location: United States Status: Offline Points: 32 |
Post Options
Thanks(0)
|
Well that screw holding the extractor on the bolt head isn't coming out. I damaged it trying to undo it, and gave up before I completely buggered it. It's stuck. I give up. Whatever the headspace is on that rifle, I'm going to have to live with it.
|
|
Canuck
Special Member Donating Member Joined: January 17 2012 Location: Agassiz BC Status: Offline Points: 3535 |
Post Options
Thanks(0)
|
Try soaking the bolt head in penetrating fluid, for like a week, then try loosening the bolt again. If it doesn't come out, it will have to be drilled out by a machinist or gunsmith then replaced. Other than that, you might have to be happy with the headspace you have.
|
|
LE Owner
Senior Member Joined: December 04 2009 Status: Offline Points: 1047 |
Post Options
Thanks(0)
|
Well since the cases that cracked were Winchester made and reloaded and fired 4 or more times your rifle probably has fair headspace compared to most Enfields. The Winchester cases have a well earned reputation for not lasting long when fired in the standard Enfield .303 milspec chamber, and the fairly thin rim is only one reason for this. Remington cases work well in my rifles, though mainly because I corrected headspace by fitting new bolt bodies and boltheads. Some Winchester cases have split long ways on first firing in some rifles that have had no problems with other brands. These were likely a rare instance of defective cases, but that put me off Winchester bra$ for good. Even Winchester cases that showed no damage on first firing have not lasted as long as the Remington case in my rifles. Use a different brand case and try out the tricks I mentioned, which should improve accuracy and increase case life. You might also try the thin O-ring or fishing line method for first firing to fire form to the chamber then neck size only. That way the reloaded rounds headspace on the shoulder instead of the rim. The O-ring or ring of monofilament placed ahead of the rim takes up the slack , holding the case head against the bolt face to avoid case stretching. Many swear by the O-ring. I haven't tried it because my rifles have excellent headspace and tighter than average chambers. PS There are headspace gauges that have a clearance cut so the extractor does not touch the gauge. Also Commercial .303 gauges are thinner at the rim than British Milspec gauges. The max milspec headspace of .074 is okay for safe shooting, but leaves too much slack (headgap) to expect reloadable cases. The fresh from the factory milspec headspace at .067 or less would be well within that needed to produce reloadable bra$ without resorting to use of an O-ring, so long as you start out with good bra$.
|
|
AussieInUtah
Groupie Joined: January 29 2012 Location: United States Status: Offline Points: 32 |
Post Options
Thanks(0)
|
I think that I'll try to obtain a set of No1 MkIII bolt heads in different dimensions.
That screw probably won't come out, even with extended soaking. I'll just toss the entire bolt head as soon as I find a replacement that works. That Winchester bra$ has a flimsy feel to it. I'll try the Remington bra$. The Privat Partizan bra$ that I've reloaded for my Mosin-Nagant seems good quality, so I'll try that too.
|
|
SW28fan
Special Member Donating Member Joined: July 02 2007 Location: Texas Status: Offline Points: 2951 |
Post Options
Thanks(0)
|
A quick note on Winchester 303 bra$ IT SUCKS it is slightly better than S&B but not by much the best is Privi followed by Norma then Remington.
|
|
Have a Nice Day
If already having a nice day please disregard |
|
Shamu
Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 17603 |
Post Options
Thanks(0)
|
This cubed. You might try the Okie Gauges headspace gauge it's a coin type, designed to work with both the firing pin & ectractor still fitted, it has a cutout for both so you won't harm anything & is to MOD specs, not SAAMI.
|
|
Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
|
|
Alan de Enfield
Senior Member Joined: November 01 2009 Location: Eastern England Status: Offline Points: 241 |
Post Options
Thanks(0)
|
Measure your rim thickness on the Winchester brass (probably around 0.056"-0.058". Then measure the rim thickness on the Privi brass (probably 0.060", maybe even 0.062").
You can tighten your (effective) headspace by 3 or 4 thou just by using quality cases and not 'cases built to a price'. - which unfortunately Win, Rem and S&B seem to do.
If you cannot get hold of original Mil-surp brass (HXP is the best) then get the best you can (Privi). I'm on the 10th reload (11 firings) for some of my Privi brass for all my Enfields (No1, No4, No4T and No5)
Just remember that Enfields pre-date SAMMI by a long way, SAMMI impose non-realistic dimensions on 'old' firearms so they can acommodate todays litigious society with safety.
|
|
LE Owner
Senior Member Joined: December 04 2009 Status: Offline Points: 1047 |
Post Options
Thanks(0)
|
I doubt that scrimping on brass is the real reason why so many commercial sporting cartridge cases for the .303 have thinner rims than milspec cases. IIRC .056 is the original minimum rim thickness. The .30-40 Krag has the same max rim thickness as the .303, at .064 , yet the U S Army manuals for the Krag list rim thickness at .060. Overly thick rims were a serious problem with WW1 .303 ammo, requiring gauging of rims to ensure proper functioning of the Maxim and Vickers MGs. A collector of British double rifles once told me that his .303 rifle would not close on the available .303 milsurp ammo due to that rifle having been built to the minimum commercial specs. A too thin rim will only compromise the reloadability of a case, while a too thick rim will prevent tightly built sporting rifles from operating. The U S manufacturers go by the minimum specs for sporting ammo, which is to be expected since it is sporting ammo. There are relatively few rifles other than the Lee Enfields that are chambered for the .303, but if i owned a Model 95 Winchester in .303 and the ammo I bought for an expensive hunting trip would not chamber I'd be very PO'ed. I'd be even more PO'ed if the ammo was loaded to 50,000 CUP and cracked or set back my bolt after a few dozen rounds, as happened to many 95 Winchesters when .30-06 pressures were raised from the WW1 standard of 48,000 to 50,000, and as happened to many Krag rifles when the Ball cartridge pressure was raised from 40K to 43K. The WW1 era commercial specs for .303 sporting rifle headspace were minimum .064 and maximum .068. The Lee Enfields were expected to have headspace of .067 or less after proof testing. The much looser specs of up to .074 were for rifles with significant wear. If you can obtain boxer primed milspec cases you are ahead of the game. If not then some attempt to return the rifle to minimum headspace value is in order if reloading is an important part of your shooting. After correcting headspace of my old Savage No.4 I have no problems with reloading Remington commercial cases. Winchester cases I'd used in the past seemed more brittle and poorly drawn, which made reloading them unproductive regardless of rim thickness. The cartridge companies often farm out and subcontract components, so its hard to be sure where these components may come from even if they do bear a headstamp. |
|
jorgen
Newbie Joined: September 29 2012 Location: Illinois Status: Offline Points: 7 |
Post Options
Thanks(0)
|
go on line, and look on google for how to use the standard headspace gage with out removing the extractor. it is easy. take out the magazine, hold the bolt about 2/3rds of the way to home, push the gage up from the bottom, and pull the extractor back to slide the gage onto the bolt face. position the gage like a cartidge would fit, and gently push home. if positioned correctly on the bolt face, it will slide in. don't force anything. gently close the bolt, and gently rotate the cocking handle till the slightest resistance is felt. I just did this. I found a presentation at one of the forums with photos on how to do this a while back. best regards, jorgen
|
|
jorgen
|
|
hoadie
Moderator Group Joined: March 16 2006 Location: Niagara/Canada Status: Offline Points: 9003 |
Post Options
Thanks(0)
|
Seems to me I gave Rhino a bag or two of PRIVI brass back in May.
Wonder if he's done any loadin yet? Hoadie |
|
Loose wimmen tightened here
|
|
Canuck
Special Member Donating Member Joined: January 17 2012 Location: Agassiz BC Status: Offline Points: 3535 |
Post Options
Thanks(0)
|
Luckily, my rifles all headspace nicely on a .067 guage and I don't have to remove the extractor or it's spring to perform the task. Maybe it has to do with the guage itself? I use the cartridge style guages. It is a nice feeling to know your rifle(s) headspace properly and that the locking lugs engage all the way upon cocking. I haven't used PRVI ammo yet and have been using Win/Rem exclusively with good results on and off the paper. I have just gotten into reloading but only my handguns so far, but not including my 1939 Enfield #2/Mk1 tanker model, yet.
|
|
Post Reply | Page 12> |
Tweet
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |