Some years ago when they first hit the market I bought an Ishapore 2ANo4 Mk 1 in 7.62NATO. All numbers matched, including the magazine, and the bore was perfect.
OK, using NATO ammo it functions perfectly, and using reloads made to NATO specs it functions perfectly also.
However it has two quirks that bug me.
The first is that when cycling the bolt to chamber a fresh round it wants to bind or drag. Factory ammo or reloads, it doesn't matter. It does not do this empty. I haven't fired the rifle since '98 so I can't give any up to date examples.
The second is I get signs of excessive pressure when using American made commercial ball ammo, the stuff sold by Remington, and commercial soft point type ammo of any brand. Reloads made to 308 specs show even more pressure signs, althoug they do not exceed max specs in the manuals.
The pressure signs show up as difficulty in opening the bolt and occasional sticky extraction.
I know that 7.62 Military ball is loaded to less pressure and velocity than 308 commercial hunting type ammo, but it seems strange to me that this rifle is so sensitive. Many other posters on other forums have reported no such problems with their Ishapores. Only a few seem to have this problem.
When loading my own ammo I've hit on two loads that seem to prevent this. Both using Winchester 748 and 147 to 150gr bullets. One load for military brass, and one for commercial brass. Both of these loads are below the start loads for 308 Win ammo in the manuals.
Unfortunatly nobody shows any load data that matches 7.62 ball specs.
Anyway, does anybody here have any ideas of how to cure the binding or dragging bolt? And why this thing seems to be so pressure sensitive?
Thanks,
Joe
Bolt binding / Ishapore 7.62 Nato
Moderators: Bullseye, Moderators
Bullseye,
The primers are very flat, with no cratering and the edges are not filling the primer pocket.
The cases are expanded more than I'm used to on other calibers just ahead of the case web. The R-P stuff has a very shiny area, not a ring like a case head separation, just ahead of the web area.
None of the cases show signs of excessive tool marks. To me they look normal in that reguard.
The ony empties I have are the R-P commercial ball ammo and some of my 748 loads with a 147gr FMC BT, and they both look the same.
I don't have any fired cases from ball ammo that are un-processed to compare.
Joe
The primers are very flat, with no cratering and the edges are not filling the primer pocket.
The cases are expanded more than I'm used to on other calibers just ahead of the case web. The R-P stuff has a very shiny area, not a ring like a case head separation, just ahead of the web area.
None of the cases show signs of excessive tool marks. To me they look normal in that reguard.
The ony empties I have are the R-P commercial ball ammo and some of my 748 loads with a 147gr FMC BT, and they both look the same.
I don't have any fired cases from ball ammo that are un-processed to compare.
Joe
Bullseye,
I think we're / (I'm) confused. Let me reiterate a bit.
>The bolt dragging ONLY happens when I chamber a fresh round. (I think. I haven't fired this rifle in 8 years and as I type this out I'm not sure if the binding is ONLY when chambering a fresh round, or also when extracting a fired round. I need to go shoot this thing again.) And it happens with any and all ammo. Factory commercial, factory ball or reloads.
>The signs of excess pressure, stiff bolt operation - stiff extraction, ONLY happens with commercial ammo, mostly hunting stuff, and handloads using that type of data.
Not with Military ball, or reloads using ball spec data.
Hope I've got that squared away.
One more thing / question: Somewhere, away back in the dark ages (pre-enternet) I read an article that said rifles for the 7.62 NATO and the 308 Win were throated different. So the hotter loads normally found in commercial ammo would sometimes show excessive pressures compared Military ball ammo. I believe this article was aimed more at the M1As than bolt guns, but it still could be a problem if true.
Now I haven't done any chamber casts on this rifle. That's one of the "Round-To-Its" that I haven't got round-to-it yet.
So is it possible that the chamber throat and lead on this specific rifle might not be cut properly?
Joe
I think we're / (I'm) confused. Let me reiterate a bit.
>The bolt dragging ONLY happens when I chamber a fresh round. (I think. I haven't fired this rifle in 8 years and as I type this out I'm not sure if the binding is ONLY when chambering a fresh round, or also when extracting a fired round. I need to go shoot this thing again.) And it happens with any and all ammo. Factory commercial, factory ball or reloads.
>The signs of excess pressure, stiff bolt operation - stiff extraction, ONLY happens with commercial ammo, mostly hunting stuff, and handloads using that type of data.
Not with Military ball, or reloads using ball spec data.
Hope I've got that squared away.
One more thing / question: Somewhere, away back in the dark ages (pre-enternet) I read an article that said rifles for the 7.62 NATO and the 308 Win were throated different. So the hotter loads normally found in commercial ammo would sometimes show excessive pressures compared Military ball ammo. I believe this article was aimed more at the M1As than bolt guns, but it still could be a problem if true.
Now I haven't done any chamber casts on this rifle. That's one of the "Round-To-Its" that I haven't got round-to-it yet.
So is it possible that the chamber throat and lead on this specific rifle might not be cut properly?
Joe
I was wondering about that. Your description sounds like a chamer that is cut on the short side. I'd headspace that rifle and see what the measurements are. One on the short side would cause exactly the problem you describe, difficutly seating a new round and hard extraction. The problem is one where the case doesn't have adequate room to expand and this causes an overpressure situation.
Here's the SAAMI .308 specs.
min - 1.630 Max - 1.640 (normal factory limit is 1.636)
Here's the GOVERNMENT NATO 7.62 specs.
min- 1.630 Max - 1.633
You should headspace guage it and see. You may need your chamber reamed a little.
Hope this helps.
R,
Bullseye
Here's the SAAMI .308 specs.
min - 1.630 Max - 1.640 (normal factory limit is 1.636)
Here's the GOVERNMENT NATO 7.62 specs.
min- 1.630 Max - 1.633
You should headspace guage it and see. You may need your chamber reamed a little.
Hope this helps.
R,
Bullseye
Bullseye,
The specs:
>Here's the SAAMI .308 specs.
>min - 1.630 Max - 1.640 (normal factory limit is 1.636)
~and~
>Here's the GOVERNMENT NATO 7.62 specs.
>min- 1.630 Max - 1.633
Is this the measurement from the case just ahead of the extractor grove to the shoulder? If it is they have the numbers transposed on the drawing.
Now, the two specs you have given me do explain one problem I have. I have never been able to get my case lengths consistent.
I buy RCBS dies most of the time and the set I use to reload this rifle is RCBS. So I adjust the dies to the instructions.
This set the dies to size the cases to SAAMI 308 Specs. I have difficulty chambering them in my Ishy. So now I know why.
I also have one of those chamber / case guages that you drop cases into. When I test resized cases that were not originally fired in my rifle they look to be within the the tollerences. However when I drop cases that have been fired in my rifle into the guage, they look short. Again, now I know why.
OK, now I need to shoot some 7.62 Ball ammo in the Ishy and then measure the cases and adjust the sizing die to that spec. Toss the SAAMI specs on this one.
Not long after I got the rifle I did have the head space checked. The gunsmith dropped in a NO-GO guage and the bolt would not close. But since the NO-GO guage was made to SAAMI specs, the head space could still be out I'll bet.
I think I'm gonna take up knitting
.
Joe
The specs:
>Here's the SAAMI .308 specs.
>min - 1.630 Max - 1.640 (normal factory limit is 1.636)
~and~
>Here's the GOVERNMENT NATO 7.62 specs.
>min- 1.630 Max - 1.633
Is this the measurement from the case just ahead of the extractor grove to the shoulder? If it is they have the numbers transposed on the drawing.
Now, the two specs you have given me do explain one problem I have. I have never been able to get my case lengths consistent.
I buy RCBS dies most of the time and the set I use to reload this rifle is RCBS. So I adjust the dies to the instructions.
This set the dies to size the cases to SAAMI 308 Specs. I have difficulty chambering them in my Ishy. So now I know why.
I also have one of those chamber / case guages that you drop cases into. When I test resized cases that were not originally fired in my rifle they look to be within the the tollerences. However when I drop cases that have been fired in my rifle into the guage, they look short. Again, now I know why.
OK, now I need to shoot some 7.62 Ball ammo in the Ishy and then measure the cases and adjust the sizing die to that spec. Toss the SAAMI specs on this one.
Not long after I got the rifle I did have the head space checked. The gunsmith dropped in a NO-GO guage and the bolt would not close. But since the NO-GO guage was made to SAAMI specs, the head space could still be out I'll bet.
I think I'm gonna take up knitting
.Joe
No Joe the drawing is correct. The numbers I gave were the chamber depth or "headspace." I should have been more clear about that. Here's a better drawing of the case in the chamber from Fulton-Armory.
You can see there's differences in the drawings because they're using separate reference points.
Hope this helps.
R,
Bullseye
You can see there's differences in the drawings because they're using separate reference points.
Hope this helps.
R,
Bullseye
Joe,
Being a service rifle gas gunner I can give you an equivalent load to M852.
168 gr. Sierra HPBT
CCI 34 Primer - milspec equiv.
42 gr. IMR 4895 (*)
OAL 2.800" - milspec equiv. (*)
Use 7.62mm Military brass - its thicker walled.
(*) Powder - you can start with 40.5 gr. of IMR 4895 and work up .5 gr. at a time. Also a suitable sub is H 4895. (I like the IMR)
(*) Cartridge length - you can go as high as 2.820" OAL but no higher, and that depends on the chamber of your rifle (which we already know is a little off).
Your bolt gun can take the IMR 4895 powder loads up to 45 gr. but don't try this until you get that chamber looked at for headspace. Once you get that chamber done then step up your load .5 gr. at a time, no higer than 45.
Hope this helps.
R,
Bullseye
Being a service rifle gas gunner I can give you an equivalent load to M852.
168 gr. Sierra HPBT
CCI 34 Primer - milspec equiv.
42 gr. IMR 4895 (*)
OAL 2.800" - milspec equiv. (*)
Use 7.62mm Military brass - its thicker walled.
(*) Powder - you can start with 40.5 gr. of IMR 4895 and work up .5 gr. at a time. Also a suitable sub is H 4895. (I like the IMR)
(*) Cartridge length - you can go as high as 2.820" OAL but no higher, and that depends on the chamber of your rifle (which we already know is a little off).
Your bolt gun can take the IMR 4895 powder loads up to 45 gr. but don't try this until you get that chamber looked at for headspace. Once you get that chamber done then step up your load .5 gr. at a time, no higer than 45.
Hope this helps.
R,
Bullseye
Bullseye,
I finally found my own data I've used in the 7.62 from my Ishapore.
Military Brass - WLR Primers - 147gr / 150gr FMCBT - 42.0grs Win 748
Comm Brass - WLR Primers - 147gr / 150gr FMCBT - 44.0grs Win 748
Then when I was looking for some other load data in the Winchester Components Catalog dated 99, and DUHHHHH, I found these loads.
308 Winchester:
147grs FMJBT - 45.2grs Win 748 - 2730 fps @ 45,500 psi
147grs FMJBT - 51.8grs Win 760 - 2768 fps @ 45,900 psi
Since these loads were in the 308 section and there is no mention of which brass was used, I'll "assume" it was commercial 308 brass.
So, I had the loads I was looking for right under my nose and didn't realize it.
What amazes me is my own loads that were developed without a chronograph were so close to the loads in the Win data.
Joe
I finally found my own data I've used in the 7.62 from my Ishapore.
Military Brass - WLR Primers - 147gr / 150gr FMCBT - 42.0grs Win 748
Comm Brass - WLR Primers - 147gr / 150gr FMCBT - 44.0grs Win 748
Then when I was looking for some other load data in the Winchester Components Catalog dated 99, and DUHHHHH, I found these loads.
308 Winchester:
147grs FMJBT - 45.2grs Win 748 - 2730 fps @ 45,500 psi
147grs FMJBT - 51.8grs Win 760 - 2768 fps @ 45,900 psi
Since these loads were in the 308 section and there is no mention of which brass was used, I'll "assume" it was commercial 308 brass.
So, I had the loads I was looking for right under my nose and didn't realize it.
What amazes me is my own loads that were developed without a chronograph were so close to the loads in the Win data.
Joe
2750 fps is a good all around number for .308 ammo. This is a good speed for the 150-170 grain bullets with the 1:10 barrel twist rate of the Garand. Looking at your pressure numbers you're well within the 62,000 psi max SAAMI limits.
I finally found those specs on 7.62 (M59) Ball.
Cart weight - 393 gr (25.47 gm)
Cart length - 2.8 in (71.1 mm)
Powder type - WC 846
Powder weight - 46 gr
Bullet weight - 150.5 gr (9.75 gm)
Chamber press - 50,000 psi (3,515 kg/cm²)
Muzzle velocity - 2,750 fps (838 mps)
Hope this helps.
R,
Bullseye
I finally found those specs on 7.62 (M59) Ball.
Cart weight - 393 gr (25.47 gm)
Cart length - 2.8 in (71.1 mm)
Powder type - WC 846
Powder weight - 46 gr
Bullet weight - 150.5 gr (9.75 gm)
Chamber press - 50,000 psi (3,515 kg/cm²)
Muzzle velocity - 2,750 fps (838 mps)
Hope this helps.
R,
Bullseye
WC 846 is a miltiary ball powder and can be bought at surplus suppliers. Wiedners has 8 lb canisters of surplus WC 846 for $72.
Also the commercial equivalent of WC846 is Hogdon's BL-C(2). I'd go with 46gr of BL-C(2) for the 150 gr bullet to get close to 2750 fps. Hogdon has another near equal powder in H335. Hogdon recommends a 44gr load of H335 for the 150 gr bullet.
IMR 4895 or H4895 are also very close in their burn rates to H335. 44gr of H4895 will give you the same approximate fps for the 150gr bullet.
Hope this helps.
R,
Bulllseye
Also the commercial equivalent of WC846 is Hogdon's BL-C(2). I'd go with 46gr of BL-C(2) for the 150 gr bullet to get close to 2750 fps. Hogdon has another near equal powder in H335. Hogdon recommends a 44gr load of H335 for the 150 gr bullet.
IMR 4895 or H4895 are also very close in their burn rates to H335. 44gr of H4895 will give you the same approximate fps for the 150gr bullet.
Hope this helps.
R,
Bulllseye