Random terrible flyers - ideas??

[Subwrx300]

So a buddy of mine built a new 224V and is running into a super odd issue. He will shoot 10 shots slowly and groups will be around 1" or so for most rounds BUT with 88 ELD factory ammo, he gets one or 2 that are WAAAAYYY out: 6-7+ inches out of group. Bullets are not keyholing or sideways in any way. It's simply like they got kicked dead out of group.

Here are some details of build and shooter:

• Very highly skilled shooter with gas guns. He has several top 5 and better finishes at matches (military and civilian)
• Gun is built on 24" Rainier UM (I have 26" version of same barrel and it shoots consistent .8 or better)
• SiCo QD brake
• This is second barrel and first one did the same thing.
• When new, the BCG/bolt was VERY difficult to move by hand or by charging handle.
• Tested with two scopes, same issue.
• Gas Block is located forward of end of handguard so it cannot contact directly.

Rainier offered to have him send upper in for testing buy we want to try a few things first including:

1. Checking gas tube & BCG contact
2. Borescope barrel and gas port for bad burrs/copper
3. Turn off gas system to eliminate early unlocking as variable
4. Test factory ammo again
5. Test various bullets/weights with handloads
6. ???

I can't think of other variables to check (gun has been double checked on torque on barrel nut and muzzle brake.)

I think it's either : A) gas port burr, B) something with muzzle device and gasses kicking bullet or C) bad bullets tearing jacket or similar.

Have any of you had a rifle do something similar and if so, what was fix? Any other items you think I should check? I'm scratching my head a bit with this one especially since I and a few others with similar builds and same barrel have not seen this.

Open to suggestions. Thanks guys!

 

[Bull81]

Not going to be of much help but I have a 223 with a Rainer ultra match barrel and it was doing the exact same thing with the 70 gr RDF’s. It would put 4 out of 5 into a nice little knot then throw the other one way off like that, sometimes completely off the target. It shoots the 73gr ELD’s lights out and those RDf’s were the only bullet it did that with and I never figured out why, but to this day it’s the best shooting gas gun I’ve ever seen.

 

[redneckbmxer24]

Try a different bullet/load. Both of my Valkyries shot like shit with the factory Hornady ammo (1.5 moa) but shot great with Federal and my loads. I also got 500 of the 88gr ELD's I was planning to load with and weighed and measured a handful of them and saw almost a full grain of weight variance and up to .007" difference in bearing surface lengths. After my results with the ammo and seeing that I didn't bother with them and sent them back for a refund.

IMO hornadys quality control has gone down hill hard based on this and also problems I had with the 147's.

 

[Lowlight]

Hornady makes the Federal stuff too LOL

It's made in the same place

 

[redneckbmxer24]

I think the issue is the bullets, not where the ammo is being made. 1gr of variance on a 88gr bullet and up to .007" bearing surface is just insanely sloppy.

I didn't pull any of the 90gr SMK's to weigh and measure but the 95's are +/- .001" and .06gr.

 

[Lowlight]

Try putting extra rounds in the magazine and don't run the ammo out and see if the last shot flyers go away

It is possible they had a bad lot of 88s, bullets get recalled all the time, it may have been too small to be noticed in QC.

 

[Subwrx300]

Try putting extra rounds in the magazine and don't run the ammo out and see if the last shot flyers go away

It is possible they had a bad lot of 88s, bullets get recalled all the time, it may have been too small to be noticed in QC.

I was leaning towards ammo also. He has a single lot of 300 rounds 88ELD factory and both barrels did the same with that lot. The AE75 didn't do that but he didn't shoot anywhere near the same number of rounds.

But the flyers are occur randomly in string of fire, so it doesn't seem mag related and he tried single feeding with similar issue.

I have shot 1200+ 88elds under handloads and haven't had any issues, so it seems like it could simply be lot issues.

Good advice and we will test it next week.