Sad and depressed: Shot through my laser boresighter

[Frank Alc]

Hi Gents,
I am writing here to vent my sadness. This morning I was finally sighting in my L61r in 7mm RM that I bought about a month ago (see thread Sako L61 7mm Odd serial number).
I was almost done with nice 1.6 MOA grouping at 100 meters which I consider enough for hunting. In an unforgivable mistake I took one shot with the boresighter in the barrel. I had put it again on the barrel to just take a picture for my friend who gifted me the boresighter. Then some pals came in and we talked for some time. When they left I was going to take the last shot to reconfirm zero, forgot to remove it and shot through the boresighter.
I realized of the screwup when I did not get on paper and started scratching my head. The boresighter volatilized of course.
I know I have been veeeeery lucky for the sako stood the test. Good point for Sako quality and sturdiness.
The barrel apparently withstood the overpressure with no signs of deformation. Only there is some buildup near the muzzle. I presume it is part of the remains of the boresighter.
I was so desperate that I took 2 more shots. 1 at 100 meters, didn't get on paper either. The other at 50 metes, got on paper, about 8 or10 inches left of target looks somewhat like a keyholish impact (see picture attached)
I packed everything and headed home devastated.
What I am fearing now is that I probably ruined the berrel, and may be the action too has suffered.
Would you trust this weapon again ? Or do you judge risky to keep and use it ? In case I can clean the build up and restore its accuracy ...
Any musings ?, thanks,
Frank

 

[paulsonconstruction]

You don't need a bore sighting device for a bolt action rifle. Just look down the bore & center the target while turning the scope turrets to get the crosshairs on the bullseye. You can still see the crosshairs when your eye is near the butt of the stock well enough to do this. I can easily get to within 6" or less of the bull this way. To be more precise put, a spent piece of brass in the chamber & look through the flash hole. Did it that way & got lucky once. The first shot hit dead center in the bull!!

 

[gowyo]

You can shorten your bbl an inch at a time until it starts shooting again…i killed a chrony once, I had to get it on, it made a move.

 

[Frank Alc]

You don't need a bore sighting device for a bolt action rifle. Just look down the bore & center the target while turning the scope turrets to get the crosshairs on the bullseye. You can still see the crosshairs when your eye is near the butt of the stock well enough to do this. I can easily get to within 6" or less of the bull this way. To be more precise put, a spent piece of brass in the chamber & look through the flash hole. Did it that way & got lucky once. The first shot hit dead center in the bull!!

I know, I know. It was the first time in my life I was using a boresighter. I must say it is handy and convenient. I used it because it was a gift and wanted to show appreciation to the person who gave it to me. Bad luck

 

[Frank Alc]

You can shorten your bbl an inch at a time until it starts shooting again…i killed a chrony once, I had to get it on, it made a move.

Bit it did not affect your rifle, did it ?
A chrony stands oit of the barrel.

So you think my rifle is safe to fire ? I am not talking accuracy yet but safety. I thought of scraping it altogether.
On the other hand is is a 7 mag
No way shortening the barrel. Too much noise and recoil for poor performance in a short barrel

 

[Spaher]

Some shorter barrels are quite accurate. You lose 50-100 fps for every inch reduced, but if hunting 19”-22” barrels can still give satisfactory performance although crowning the end is important. Wearing ear protection is a safety issue in my opinion as my left side hearing loss is an indicator.
If no obstruction which can verify by looking down barrel & run a cleaning rod thru with enough cleaning patches to make it tight I would think it is safe. But clean the heck out of it using copper brushes & letting the solvent sit a few minutes, then repeat again.
I am assuming no bulge on the barrel from the incident, if there is a variation then barrel should be shortened & recrowned.

 

[gunner620]

I think that a good cleaning would be in order but you already mentioned that, then I think it would be safe to shoot ( your choice). provided you find no other damage. You might also consider setting up in fixture and firing it remotely if possible. Just my 2 cents. Be safe and let us know how it shoots, hope you will be pleasantly surprised,

 

[gunner620]

Agree with Spayer as well, he beat me to posting as I was writing.

 

[bloorooster]

Did you recover the bore sighting tool? Not sure what type was used, but it’s possible that it may have squirted out of the muzzle just enough ahead of the bullet to reduce the damage. I think there is a bit of air pressure ahead of the bullet as it travels the lands.

One could use a magnifying lens, like a jewelers loom or similar, to visually inspect the muzzle and crown. A bore light from the chamber end would help. Catastrophic damage will be rather obvious. Scratches or gouges may be present.
Clean it as previously mentioned, and then tight patch it , exerting slow even pressure on the cleaning rod, pay attention to any changes in resistance as the patch travels along the full length of the barrel.
Depending on how deep the bore sighter was inserted into the bore, try to concentrate efforts to check that point. If it appears to be clear…it should be safe to shoot.
At least..a new crown will definitely be in order , possibly cutting some length away to clear the damage.
Worse case..have it rebarreled completely.

BTW..sorry to hear of this mishap…I remember your were very excited about this rifle when you found it. Best of luck!

 

[Frank Alc]

I will clen it thoroughly and check if it can shoot again. It will take me some time (work ahead). I will post the results when available.
Thank you for your opinions and advices

 

[Frank Alc]

This is the type of boresighter shot and the only two pieces I was able to recover

 

[gowyo]

I ringed the bbl on my Ruger m77 .270. Snow/ mud. You could just see a ring. I had the smith cut off an inch and recrown it. It was nowhere near as accurate prior to that ‘surgery’. I also bought a 722 rem in 257 bob for cheap. You could see a shadow on the action side of the front sight base, similar story. Sako made AV 7mm Rem mags in their carbines. 18.5” barrels.

Just sayin’, I wouldnt toss it yet.

 

[bloorooster]

This is the type of boresighter shot and the only two pieces I was able to

Was the tenon made of plastic or aluminum?
The part that inserts into the barrel?

 

[Frank Alc]

Was the tenon made of plastic or aluminum?
The part that inserts into the barrel?

I do not know for sure. I think it was made of a metallic rod (aluminum, tin, perhaps iron or steel, who nows) covered in plastic. I know there was a metallic core bcause the end was threaded to screw in different diameter tips for different calibers.
(Btw, Bloo. Thanks for your condolences. I had been long looking for an L61 in 7 mag and felt really lucky when I found this one. I'll see if I can make it shoot again. You know it is not easy in Spain to gunsmith firearms. Regulations are very restrictive regarding modifications and such. Also as a consequence of that there are very few (if any) competent gunsmiths who can undertake shortening or changing a barrel with confidence (not frequent jobs). Something that is routine in the States it is not here.

 

[kevinlg]

I would try to "lead slug" the barrel.
Find a dead soft lead slug of approximate bore diameter.......and upset it in the bore......then slowly push towards the muzzle.
Very small bore diameter variations can be felt.
Repeat a few times......to confirm any findings.

Hope this helps.

 

[P04R]

Sorry about your mishap. Lots of good advice on this thread already. Here's my take. Don't worry about the action. It's completely fine. Barrel obstruction so close to muzzle will not cause such over pressure to damage the action. But I do think the barrel is most likely ringed/bulged at the point where the bullet impacted the stem of the boresighter. By cutting the bulge off and squaring and re-crowning the muzzle you should be fine, unless the barrel got way too short for the caliber. I think 20'', or 51 cm is still workable for 7mm Rem Mag, though longer is better in this case.

You can see even the tiniest bulges in the reflections inside the bore when viewed against an uniformly lit background (a white wall for example). The bulge shows up as a darker ring all the way around the bore on one spot, hence the name "ringed bore". Bigger bulges can be seen on the outside of the barrel too. The exact spot can be measured by the lead slug method described above by Kevin. For all inspections and measurements the bore should be as clean as possible, so that's the way to start.

 

[HelSako]

It is safe to shoot, the pressure at muzzle is very low. Clean it and test it. if you have still problem in accuraty then check the muzzle and you can try to smooth it by lapping with lead bullet and diamond paste carefully

 

[Frank Alc]

Thanks all. Regarding the lead slug method that I would like to try. Where can I find a calibrated 7mm slug ? Are they in the internet ?
I have contacted a friend who is a certified CNC lathe machinist. I asked him about turning a lead slug. Didn't like the idea. Says lead is not nice to work with. He suggested an aluminum slug. He said it is very easy to turn and the result should be good. Also suggested a copper slug. He said he can drill and tap the slug so that I can screw a cleaning rod to push it along the barrel back and forth and "sense" bulges if any. He suggested also making a set of slugs with increasing diameters. What do you think ?
In case aluminum or copper is feasible what is the exact diameter the slugs should be turned to ?
The 7mm caliber lands diameter (277 thousands), the groove diameter (284 thou) or something in between ?

 

[HelSako]

You can use 22lr lead bullets, pump them up with benchpress and hammer it to barrel (brass or aluminium between) you can drill hole for rod. Make several so you get good feeling about the barrel

 

[Frank Alc]

You can use 22lr lead bullets, pump them up with benchpress and hammer it to barrel (brass or aluminium between) you can drill hole for rod. Make several so you get good feeling about the barrel

Hel, can you explain the above procedure in more detail ? I have never slugged a barrel before and would deeply appreciate if you could lecture me on it.