JSAR Accuracy

[Yuccacapt343 0]

Since I purchased my JSAR, I have only had the opportunity to take her to the the range twice.  As with all of my older rifles I sight them in at 100 yards. After that I rarely shoot at any distance less than 200 yards. The first time I took my JSAR out, it took me nearly 50 rounds just to get it sighted in at 100 yards! Frustrated and out of ammo, I called it a day. A couple of days ago, I gave it another try. For about the first 20 rounds, I was shooting 2 inch groups at 200 yards on steel plates. After the first 20, the groups started getting larger and larger until I wasn't hitting the plates at all. Again, at 50 rounds, I called it a day. My question is has anybody else experienced accuracy issues as the barrel heats up? I'm shooting 150 g JHPBT. These are the same rounds I run through a Garand, 03, 03A3 and 1917 without a single issue. Any help would be greatly appreciated!

Wayne

 

 

 

 

[ArtR 0]

Have you gauged the throat and the muzzle? Is the barrel bright and shiny or is it dark and pitted. It is quite possible that the barrel is shot out or someone has aggressively tried to clean the barrel and in the process worn the muzzle. A worn muzzle is the last thing the bullet touches. Are your first shots fairly on target and then open as you continue to fire? As the barrel heats up, accuracy can diminish in a barrel that has not been treated to reduce stresses. Just some thoughts from an old competitive shooter. ArtR

[Yuccacapt343 0]

Good Morning Art, that is exactly the input I was looking for! I have not gauged the muzzle and throat as of yet. I have a gauge ordered. The barrel is bright and shiny without signs of pitting. First shots are fairly accurate then open up as barrel heats up. I really appreciate the help!

[Ed Johnson 0]

There is heat....and then there is heat. Much of this depends on how fast you shoot, along with the other factors you guys have mentioned. I'm also concerned that it took 50 rounds to sight the rifle in at 100 yards. I'm wondering about the barrel itself. And unless you are firing very fast semi-auto, the spread at 200 yards seems excessive.   ej

[Yuccacapt343 0]

Hey Ed,

I am not a fast shooter. I'll load 5 rounds and it probably takes me 3-4 minutes to go through the five. Then I'll look through my sighting scope for a rew minutes, pick up my brass and then start the whole process over again. I agree with the amount of ammo it took to sight in at 100. But when I took it out again, I was able to hit 200 yard steel without issue for the first 20 or so rounds?

[Ed Johnson 0]

OK. that sounds a little better. Might still want the barrel checked by someone. Maybe you can determine WHICH WAY (direction) the group starts to move after the barrel warms up?

[Joseph Scott 0]

I would suggest checking your rear and front sights for looseness.  It is unlikely that your timed shooting is overheating the barrel.  Also check that all the bottom screws are tight.  Even worn barrels don't vary like that.

[Yuccacapt343 0]

Ed,

Sounds good. I will will take it out again to determine.

Joe,

I thought about the sights and checked them for tightness while I was cleaning this morning. They appear to be tight. The screws are a different story. When I first purchased the rifle, I inspected it but don't recall checking the screws. After my first range visit, I checked the screws and they were all very loose so I tightened them up. I just checked the screws again and they are loose again? Not as much as before but noticeably loose?

 

 

[Joseph Scott 0]

The large head screws are supposed to have a internal star washer under the head and a flat washer against the wood.  The flat washers screw onto the threads until they get to the reduced diameter under the head.  This allows the screw to rotate while the flat washer bears against the wood without turning.  Check that the wood is flat under the washers and not deformed. Also check that the square recoil keys are in place over the trigger, in forearm and that star washers are not flattened.

[Yuccacapt343 0]

Hey Joe,

Sent you a PM.

[Yuccacapt343 0]

With the help/advice from the above members, it appears my accuracy issues have been resolved. Upon inspecting the barrel, I determined the MW = .5! Crown is in excellent condition. Since it appeared the mounting screws where coming loose every time I fired the weapon, I removed the screws and found all of the star washers where flat. One of the mounts was missing the flat washer so the star washer was just burying itself into the wood. Joe supplied me with the correct flat and star washers. After reassembly, it was time for another range visit. Rifle sighted in at 100 yards in 10 rounds. First shot at 200 yards on a 1' square steel plate was dead center! Any variation from dead center for the remaining 40 rounds was strictly me (still getting used to its 2 lbs trigger pull) and my old eyes. After 50 rounds, all mounting screws still tight!

I want to thank everybody for your advice and expertise! I very much appreciate the help!

Wayne

[Ed Johnson 0]

Good !  It is very nice to have a happy ending.....!