Spanish Mauser 7X57 reloads

[Merc]

I have a sweet looking 7X57 M1916 1931 Spanish Mauser that seems to be in nice mechanical shape. It has a nice clean bore with crisp rifling but doesn't shoot as well as I think it should. I've never grouped better than 12 inches at 50 yards with reloads. Factory ammo was worse.

My reload formula includes using flat based 7mm 139 grain .284" bullets and 1 grain over the starting load of BLC-(2) powder.

I also have a 1944 Lee-Enfield No. 4 Mk 1* that's also in nice shape mechanically that didn't seem to like boat tails but will shoot flat bases very accurately also with 1 grain over starting load of BLC-(2) powder.

Has anyone had better luck with a different 7X57 reload formula than what I'm using?

Merc

[kcw]

I have a sweet looking 7X57 M1916 1931 Spanish Mauser that seems to be in nice mechanical shape. It has a nice clean bore with crisp rifling but doesn't shoot as well as I think it should. I've never grouped better than 12 inches at 50 yards with reloads. Factory ammo was worse.

My reload formula includes using flat based 7mm 139 grain .284" bullets and 1 grain over the starting load of BLC-(2) powder.

I also have a 1944 Lee-Enfield No. 4 Mk 1* that's also in nice shape mechanically that didn't seem to like boat tails but will shoot flat bases very accurately also with 1 grain over starting load of BLC-(2) powder.

Has anyone had better luck with a different 7X57 reload formula than what I'm using?

Merc

Curious that you're getting such a spread at such a short distance. Any evidence of keyholing, such as slightly egged/elongated holes in the target? Have you checked for throat wear? The reason I mention the possibility is because I once had one of those Soviet reclaimed 98K's which, to the naked eye, had a perfect bore; and yet it keyholed @ 25yds. Ultimately found that at least a full inch of throat/barrel was burned out. I can't imagine the circumstances under which a soldier would fire so fast to cause that to happen, until I think about what happened on the Russian front. Anyway, you might want to confirm just how much "jump" you're dealing with in the chamber.

[Merc]

Curious that you're getting such a spread at such a short distance. Any evidence of keyholing, such as slightly egged/elongated holes in the target? Have you checked for throat wear? The reason I mention the possibility is because I once had one of those Soviet reclaimed 98K's which, to the naked eye, had a perfect bore; and yet it keyholed @ 25yds. Ultimately found that at least a full inch of throat/barrel was burned out. I can't imagine the circumstances under which a soldier would fire so fast to cause that to happen, until I think about what happened on the Russian front. Anyway, you might want to confirm just how much "jump" you're dealing with in the chamber.

No keyholes, just accuracy issues.

Flats can sometimes be more accurately fired through worn barrels from what I've learned from reloading and firing my No. 4. I thought the bore was ok but the original factory .303 ammo was FMJ BTs and was all over the target. I reloaded with flat base soft points and it fired good groups that were improved further by increasing the powder charge by one grain over minimum. I was hoping for similar results in the Mauser but wanted to see if anyone had achieved success with a different formula.

The original stock on the Mauser was sportrerized and now only the base remains. The hand guards and barrel bands are long gone. I tried it and it shot very erratically but no keyholing. I floated the barrel somewhat and noticed a lot of improvement but still room for more.

I found an exact duplicate of my Spanish Mauser at an antique shop with an original maple stock but the barrel was all shot out. I bought the rifle and swapped stocks and the results are pretty much stayed the same but at least now, all shots are on the paper at 50 yards. That's what had me leaning towards trying a different reload formula. The muzzle doesn't swallow a bullet but a 'smith will have to tell me if the throat is worn.

[kcw]

No keyholes, just accuracy issues.

Flats can sometimes be more accurately fired through worn barrels from what I've learned from reloading and firing my No. 4. I thought the bore was ok but the original factory .303 ammo was FMJ BTs and was all over the target. I reloaded with flat base soft points and it fired good groups that were improved further by increasing the powder charge by one grain over minimum. I was hoping for similar results in the Mauser but wanted to see if anyone had achieved success with a different formula.

The original stock on the Mauser was sportrerized and now only the base remains. The hand guards and barrel bands are long gone. I tried it and it shot very erratically but no keyholing. I floated the barrel somewhat and noticed a lot of improvement but still room for more.

I found an exact duplicate of my Spanish Mauser at an antique shop with an original maple stock but the barrel was all shot out. I bought the rifle and swapped stocks and the results are pretty much stayed the same but at least now, all shots are on the paper at 50 yards. That's what had me leaning towards trying a different reload formula. The muzzle doesn't swallow a bullet but a 'smith will have to tell me if the throat is worn.

You can get an idea of how much "jump" your rifle might have by merely dropping a bullet into the downward pointed chamber and then running a fired case with a slightly crimped mouth in behind it. Be sure to get the rim of the case under the extractor before you run the bolt fully forward and turn it down. If the case mouth has been suitably "crimped", the bullet will be extracted with the case. The OAL of the resultant case/bullet assembly will give an idea of just how far your bullet is moving forward before it engages the rifling. This process won't tell you the total condition of the throat, other than if the throat is worn well forward of spec. , which may be all you need to know anyway if it is.

[Merc]

You can get an idea of how much "jump" your rifle might have by merely dropping a bullet into the downward pointed chamber and then running a fired case with a slightly crimped mouth in behind it. Be sure to get the rim of the case under the extractor before you run the bolt fully forward and turn it down. If the case mouth has been suitably "crimped", the bullet will be extracted with the case. The OAL of the resultant case/bullet assembly will give an idea of just how far your bullet is moving forward before it engages the rifling. This process won't tell you the total condition of the throat, other than if the throat is worn well forward of spec. , which may be all you need to know anyway if it is.

I'll have to try that.

Once the loose bullet has been pressed into the lightly crimped cartridge by the bolt, how close in overall length would you expect them to be to an unfired cartridge if the throat is within spec? Close to the same size?

There's not much space on the case neck, so is it reasonable to assume that the further out to the end of the case neck the bullet seats, the more erosion has occurred to the throat?

How much throat erosion can a rifle sustain and still shoot reasonably well? My Lee-Enfield No. 4 Mk 1* might tell us that since it seems to prefer flats to boat tails which could be caused by throat erosion.

I knew there had to be a simple way to check throat erosion. Thanks for the tip.

Merc

[kcw]

Merc,
That method is best used in a comparative fashion. For instance, I have a number of M1917 rifles all of which have nice bores. Using the previously mention technique, the average "jump" between the OAL of a known GI factory M2 round, and the OAL of an M2 bullet pressed into the case mouth, runs around .205". Using that average as the "norm" I can ROUGHLY gage the throat wear of other M1917 rifles. In the case of the previously mentioned 98k, the bullet was completely air borne in the excessive "free bore". The gas rushing by it caused it to tip slightly before it slammed into the lands, which resulted in the bullet going down the barrel in a "cocked" fashion. The bullet immediately went into a wobble upon exiting the barrel, which resulted in key holing at only 25yds.
I have no idea what the Spanish arsenal standards were, but you might want to try my .205" inch figure as a comparison guide. Have you printed any rounds at 100yds? I ask because tumbling might be difficult to detect at 50yds, but might better manifest itself @ 100yds. Obviously something is wrong if you have that kind of spread @ 50yds with BOTH your reloads AND factory loads. If you observe nice, round holes @100yds I think you can eliminate key holing/tumble as an issue. The info for the 7x57 in my "ancient" Lyman loading manual notes: Most 7m/m's are imported rifles and their grove diameters can vary considerably. We recommend that you slug your barrel to determine its exact groove diameter.". According to the manual the nominal groove diameter is .2865. There are similar admonishments regarding groove diameters for the 7.65 Argentine, Jap rifles; and especially the 303 where it is noted: "In rifles we have checked, diameters range from .309 to .317. We suggest slugging your barrel ...and using the jacketed bullet which corresponds most closely to your groove diameter (.311-.312 or 313.). If your groove diameter should be large (over .314) results will be poor". I mention the previous info because its possible that you might be dealing with oversized barrels in both the 7mm & 303. Going the other way, I have a WWII Australian #1 Lee Enfield with such a TIGHT bore that I use 308 bullets in it. The 308 bullets I've recovered @ the range show no sign of gas "blow by".

[Merc]

I'll have to try shooting the Mauser again at the 100 yard targets and take a closer look at the resulting bullet holes. I'm pretty sure they were round. I should probably do the jump measurement first before shooting to see what that looks like. In your experience, does a fully resized reloaded case from which a bullet has been pulled have the right amount of remaining crimp to properly seat a dropped bullet or would a partially crimped case that's been fired work better?

Merc

[kcw]

I'll have to try shooting the Mauser again at the 100 yard targets and take a closer look at the resulting bullet holes. I'm pretty sure they were round. I should probably do the jump measurement first before shooting to see what that looks like. In your experience, does a fully resized reloaded case from which a bullet has been pulled have the right amount of remaining crimp to properly seat a dropped bullet or would a partially crimped case that's been fired work better?

Merc

Use a fired case and merely turn the lip of the mouth in a bit, maybe in several places, with a needle nose plier (ect). You just want the case mouth to have enough grip to pull the bullet back out without the bullet slipping., but yet want the case mouth to slip over the bullet without a great deal of pressure. It's a "happy medium" sort of thing. The test should be repeated three or four times to insure that the brass isn't pulling off the bullet while retracting it from the chamber.

[Merc]

OK, thanks. I'll let you know how I do.

Merc

[Merc]

Use a fired case and merely turn the lip of the mouth in a bit, maybe in several places, with a needle nose plier (ect). You just want the case mouth to have enough grip to pull the bullet back out without the bullet slipping., but yet want the case mouth to slip over the bullet without a great deal of pressure. It's a "happy medium" sort of thing. The test should be repeated three or four times to insure that the brass isn't pulling off the bullet while retracting it from the chamber.

KWC,

Too bad this thread is buried under the current title. This is pretty valuable info that lots of troubled shooters who don't know about would find useful.

Merc