7mm Mexican Mauser this can't be good.

Muskyhunter1

Muskyhunter1

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I shot 175 grain slugs out of the 7mmx57mm Mauser 98 today. I always knew the bore was dark but it is there. I shot 5 rounds and never hit the target once at 50 yards. Moved the target up to 25 yards. One bullet turned around and went in base first. Don't know what the dark rooster tail on the paper is from but it cant be good.

Bullets too long or rifling finished???? The gun was a gift so I got nothing in it..

Your thoughts please.


7mmroostertail25ygs_zpseb6fbdc2.jpg


7mmgoup25yds_zps9b16a581.jpg
 
I can't see pics, but tumbling bullets result from bullets not stabilizing, and an obvious contributor to that problem is rifling not doing it's job.

I have seen this a lot with heavily leaded barrels, but with no rifling at all it would have the same results.
 
Muskyhunter1 said:
I shot 175 grain slugs out of the 7mmx57mm Mauser 98 today. I always knew the bore was dark but it is there. I shot 5 rounds and never hit the target once at 50 yards. Moved the target up to 25 yards. One bullet turned around and went in base first. Don't know what the dark rooster tail on the paper is from but it cant be good.

Bullets too long or rifling finished???? The gun was a gift so I got nothing in it..

Your thoughts please.


7mmroostertail25ygs_zpseb6fbdc2.jpg


7mmgoup25yds_zps9b16a581.jpg
Click to expand...
That can be a problem with dark bores, heavily pitted rifling do the same as a worn out bore. You may give it a good cleaning but rifling is probably too pitted to stabilize the bullet.

Joce
 
svt1940 said:
That can be a problem with dark bores, heavily pitted rifling do the same as a worn out bore. You may give it a good cleaning but rifling is probably too pitted to stabilize the bullet.

Joce
Click to expand...

Dark bores are just dark bores, they can be worn, or pitted. You should slug the bore and get the correct sized bullet. It might be worn and need a slightly larger bullets.
BTW "175 grain slugs" are you shooting lead or copper jackets?
 
inspect the crown, my dad has a .303 that was tumbling every fourth or fifth bullet - re-crowned it and problem was solved.

if you get too frustrated you could always give it to me ;)
 
Can the OP post pics of what the crown/muzzle look like??

Keyholing and throwing bullets all over the target at 25 yds suggests it needs recrowning (to me-anyway:D)
 
The dark smudge is called a "comet tail". It is a spray of lead coming out the side of the jacket as the bullet is in the process of disintegrating in flight. My guess is that the rough bore is what is compromising the structural integrity of the bullet.

I have seen similar failures with Remington 55 grain Core-Lokt HP out of a 1:7 rifled 5.56mm barrel. In that case, the cause was high rate of rotation combined with a very thin jacket.
 
Good idea to check the crown. I'd clean the bore well with JB paste and a de-coppering agent. Maybe try a couple of different 150/154 gr flatbase bullets to see what happens. Your target is showing a lot of holes. What is the 5 rd group size off the bench @ 25 yds? It's a good idea to check if the metal stock sleeve for the rear guard screw is in place and then snug up the guard screws tight before shooting.
 
If that's an original Mexican milsurp, be careful before you go nuts on the crown - any alteration, even if it makes it shoot better will negatively affect value. You can tell from inspection if the crown's a likely culprit, and for it to be the sole course of what you've described, it would have to be ugly.

I usually see this when a bore is worn out and/or a bullet is undersized. Aside from "dark", what is the bore condition? Does it tear up patches? Have you slugged it? If the rifling is still pronounced and the barrel isn't damaged (e.g. "ringed", rifling missing, etc.) there could be things you can do to make it shoot better. After a thorough cleaning, you could "lap" the barrel, and if it's not still like coarse sandpaper, but oversized, you could try cast bullets.
 
Don't throw it away. Soft alloy cast bullets and tweak the powder charge.
I've done the same thing with an old Winchester lever. I got it cheap because it keyholed bullets.
And yes the rifling is toast; well mostly. Went to an oversized lead bullet and messed around with different charges. 7-8 deer later it is obviously working well.
Slow down the bullet and get a soft, relatively long bullet. IIRC Waters said in "Pet Loads" that the 7 X 57 doesn't hotrod up well. It works awesome as it was designed. Kind of like a 30-40 Krag.
But you do need to slug the bore and do a chamber cast STAT.
1st thing is ascertain what you are dealing with.
 
Soon as I seen the target, Old Milsurp rifle + tumble holes= bad Crown.


Given the unknown condition of the rifle, it needs a deep clean with a heavy bore solvent and then slug the barrel for accurate dimensions of lands and groove.
 
Could be but it's a military rifle, they typically had longer ( and usually heavier than a hunting load too) bullets in the old Milsurps with rate of twist to stabilize the original loading. A fast load and / or the lesser bearing surface of a shorter bullet might cause it to skid over worn rifling.
Stay at or below the original loading with a bullet which is similar in profile to the original load and it should work.
Might have to go to a cast bullet with a gas check though. But it might pay off big time to tweak it.
But until it gets a chamber casting and the bore slugged its all supposition; I think we can agree on that fact, correct?
 
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