Help with 7.62 Nato

[rmkey]

Excellent answers and videos on headspace! I ordered the forceps. But the force required to chamber a round is excessive due to exceptional pressure needed to force the extractor up and over the cartridge being chambered. I should think if you remove the bolt you should be able to move the extractor by thumb. It won’t move without using a screwdriver so it stands to reason forward bolt pressure is not enough to move the extractor upward to allow it to close over the recessed cartridge rim into the extractor grove. I much really slam the bolt hard to chamber a round. Then it fires and extracts the empty case easily. The extractor spring is too strong.
Can you force the extractor up by finger pressure after reassembling?
Thanks for your replies. Headspace is not the problem.

 

[Uncle Ed]

I just checked a No.1 and No.4 Enfield and I can not move the extractor with finger pressure. I no longer have a Ishapore Enfield 7.62 rifle to look at.

I'm wondering if these 7.62 Enfields have a different extractor than a .303 and were replaced by mistake. I have never had any Enfield with your problem.

 

[Bindi2]

7.62 use a different extractor. The 303 will not work.

 

[rmkey]

Ed. Thanks very much for your replies. I’m mystified. The extractors appear the same on both Ishapores. I have ordered new parts. You may be correct that they may have 303 extractors.
I will get the third one out and take a look.
You have answered a question for me about the fact you can’t push the 303 extractor by finger pressure. Something is not right it seems since 2 different guns are having the same issue. I won’t give up and if I do I know a smith.
Again thanks for your help.

 

[mac86951]

Chamber dimensions and headspace gauges can vary by country, examples below.

British Enfield L42 A1 7.62 headspace gauges.
GO 1.628
NO-GO 1.635

British L1A1 7.62 headspace gauges.
GO 1.6325
NO-GO 1.643

There is no published headspace data for India made Ishapore Enfield 7.62 rifles, BUT my well used 2A1 would close on my GO gauge at 1.630.

The max American SAAMI .308 headspace is 1.640 and would be a Field gauge.

Your head clearance is the amount of air space between the rear of the case and the bolt face. And this is the distance the case must stretch to meet the bolt face when fired. This case stretching acts like a cars shock absorber and reduces the amount of bolt thrust. Meaning it is better to have .003 or more head clearance and put less force on the locking lugs.

NOTE, a .303 Enfield rifle at max headspace of .074 and a rim thickness of .058 will have .016 head clearance. This would be safe to shoot but would be hard on the brass as far as reloading is concerned.

Question, will your bolt close on loaded factory ammunition without resistance. You can use a black felt tip marker and color the case shoulder and base of the case and see if any rubs off. If the factory ammunition chambers hard it can cause extraction problems because the case can not spring back from the chamber walls.

Pacific Tool and Gauge offers three lengths of headspace gauges per rifle caliber. In order from the shortest to longest, they are: GO, NO-GO, and FIELD:

1. GO: Corresponds to the minimum chamber dimensions. If a rifle closes on a GO gauge, the chamber will accept ammunition that is made to SAAMI’s maximum specifications. The GO gauge is essential for checking a newly-reamed chamber in order to ensure a tight, accurate and safe chamber that will accept SAAMI maximum ammo. Although the GO gauge is necessary for a gunsmith or armorer, it usually has fewer applications for the collector or surplus firearms purchaser.
   
   
2. NO-GO: Corresponds to the maximum headspace Forster recommends for gunsmiths chambering new, bolt action rifles. This is NOT a SAAMI-maximum measurement. If a rifle closes on a NO-GO gauge, it may still be within SAAMI specifications or it may have excessive headspace. To determine if there is excessive headspace, the chamber should then be checked with a FIELD gauge. The NO-GO gauge is a valuable tool for checking a newly-reamed chamber in order to ensure a tight and accurate chamber.
   
   
3. FIELD: Corresponds to the longest safe headspace. If a rifle closes on a FIELD gauge, its chamber is dangerously close to, or longer than, SAAMI’s specified maximum chamber size. If chamber headspace is excessive, the gun should be taken out of service until it has been inspected and repaired by a competent gunsmith. FIELD gauges are slightly shorter than the SAAMI maximum in order to give a small safety margin.

Oops typo; order of shortest to longest is GO; Field; NO-GO. You're explanation corrects it, just wouldn't want anyone skipping over that part.

 

[rmkey]

Well I ordered the parts as insurance case I messed up so I
decided to dismantle the bolt head, extractor and extractor spring. Cleaned all in brake cleaner and lubed with dry lube. Cleaned all parts throughout. Then polished the extractor face and lip with rouge with a Dremel. I Relieved a little tension on the spring via needle nose pliers. Took a very little
off the rough claw edge of the extractor and polished. Reassembled and viola positive feed and extraction! I have extra springs and extra extractors on the way as they seem the most likely replacement parts. Couldn’t have done it without you guys help. It’s not pleasant breaking down and and especially reassembling but for a gun that’s been shipped with black “paint” and cosmoline it may be essential for proper functioning. Both guns are now in the white and wiped down with ballistol. May finish with Cherakote eventually. Happy end of story!

On a different note the cartridge case exhibits blown out shoulders but I plan to bump them about 0.002 to 0.003 and neck size for 0.002 constricton . I have a wildcat 30-30 with necks blown out just enough to get proper bullet seating and necks reduced to.264. It’s called a 6.5 BRM by Arther Brown and works great. Just have to keep 308 cases dedicated to the Ishapore.

 

[Bindi2]

Leave the shoulder alone until you have pressure closing the bolt. The chamber is large to accommodate the washing and mud for a very good reason. Don't Full length and then just enough for bolt closure. I use a Lee neck collet die. The quality of the brass used dictates how many reloads you get with minimal sizing . These are not match chambers.

 

[rmkey]

Leave the shoulder alone until you have pressure closing the bolt. The chamber is large to accommodate the washing and mud for a very good reason. Don't Full length and then just enough for bolt closure. I use a Lee neck collet die. The quality of the brass used dictates how many reloads you get with minimal sizing . These are not match chambers.

Thanks for the info. Needless to say I won’t be using Lapua brass.i have federal and rem that I don’t use as well as military I can remove the primer crimp. I also have the lee collet dies. Thanks For the tip. Over size chambers for Washing and mud? That don’t sound good! Guess function more important than accuracy and they must not have had proper cleaning equipment. I’m used to shooting precision rifles. Even so those tiny notch and post sights are minuscule anyway. I have tons of milsurps- I just like them to function as designed. Us military rifles don’t have such huge chambers particularly the M40. Not even my 1903 a3 or the 1917 ASR’s as large. But it is what it is!