Help needed in diagnosing an accuracy issue on a Bergara...

[sns2]

Picked up a Bergara B14 Ridge. Gun is accurate. Have done some initial load development with multiple bullet weights and typically accurate ammo (ELD-M, GameChangers, MatchKings). Have been able to get 5/8" to 3/4" five shot groups. Gun likes RL17 best.

Now here is my query... I know that is accurate, but like all loonies, I am chasing greater accuracy. The gun will typically shoot three shots touching and then throw the other two close together. I should also note that the gun is not really sensitive to seating depth either.

The B14 Ridge has the same stock as the Hunter model, but with a #5 contour barrel. It is a glass reinforced polymer job with pillars, so stiffer than a Ruger American or Savage Axis type real el cheapo. It also has a type of "duratouch" non-slip, soft coating. The whole stock has this coating, including the recoil lug area. It is like it is dipped. My thought is that bedding the recoil lug will help this throwing of shots 4 & 5 away from shots 1-3. My buddy thinks that because because the recoil lug is fairly snug to begin with, and the stock is a honeycomb design in front of the recoil lug, that it will be difficult to bed, as not much to hold on to. I think if I grind some out, and drill some holes, the bedding material will have lots to adhere to.

Which direction would you look? Bedding? Something else?

I am all ears except for "It's already accurate enough." I know that, but want to see if I can make it a consistent 1/2" gun when the guy behind the trigger does his part.

Thanks in advance for your suggestions and/or diagnosis.

 

[Canhunter35]

Bedding will not hurt it and might help. Go for it and see if it helps

 

[Crowe284]

If the first 3 are always really close and it's always the last two that are flyers, I'd tend to think it's a barrel heat issue. If it's me and I'm working with a hunting rifle, three shot groups are plenty good. I've never had to shoot more than twice at an animal (one and quick follow up kinda thing) and have never worried about 5 shot groups. If I was developing a load for a match rifle where 10 shot strings were the norm, I'd go about it differently. All of my hunting rifles have loads developed with three shot groups and verified with multiple three shot groups. Anymore, I shoot 3 shot groups at 440 yds for load development and only really shoot at 100 to adjust or verify zero. I've seen a ton of time and components wasted chasing 5 shot 1/2 minute groups in a thinner barreled hunting rig . If I can get a rifle to shoot 1/2 minute with a load that has single digit ES and SD, I'm done. Just my opinion. Good luck to you and as stated the bedding can't hurt.

 

[Trnelson]

IDK how quickly you are firing your groups. You may be witnessing an optical illusion from the heat dissipation of the barrel causing a vertical dispersion.
Is this a bench rifle or a hunting rifle? If you are seeing consistent 0.5MOA three shot groups why are you firing any more?? Seriously. You'll waste 90% of your barrel life chasing that last 10% of accuracy to get from 0.5 to 0.3 MOA at 100yards. Why?!? It's literally 0.2094" or less than 1/4". Not a critter in the world will know the difference even at 1,000 yards 0.5MOA is less than 5-1/2".
How often in a real hunting situation will you have an opportunity to fire more than one? How about two? I can tell you I've only sent a second shot a handful of times in thirty plus years and I've never sent a third. Ever.
If you don't like or aren't satisfied with the bedding certainly change it. There's a lot of folks whom will read this thread thinking man, I wish I could get my rig to do a consistent 0.5MOA.
Have fun with that rig bud!

 

[mrjashu]

I have a Ridge in 6.5CM and I bedded it with Devcon. I ground portions of the stock with a dremel and bedded it from the rear tang up to and including the knox. I did the bedding before I really got serious about load development with it but for the factory ammo at least I didn't notice a huge change in the groups...but it gave me peace of mind.

 

[sns2]

I have a Ridge in 6.5CM and I bedded it with Devcon. I ground portions of the stock with a dremel and bedded it from the rear tang up to and including the knox. I did the bedding before I really got serious about load development with it but for the factory ammo at least I didn't notice a huge change in the groups...but it gave me peace of mind.

I would love to see a few pics of exactly how you tackled it. What kind of groups are you getting?

 

[stirner]

You never did say if it is always the 4th and 5th shots that fly. If it is, you may have the same problem that I encounter too frequently. You get 3 or 4 shots in a nice tight group, then start thinking about the group, instead of thinking about shooting the next shot. You don't hold the gun with the same shoulder pressure, maybe it's canted a little, or you're not on the bags in the same place, the crosshairs didn't line up on the bull so you force the rear bag sideways and keep the pressure on the bag, or you're not paying attention to your breathing. All you can see in the scope is that tight little group and that is where your mind is focused. It's the attention to detail, and consistency in your routine.

It's the reason that the guy at the carnival can hand you the mallet and challenge you to hit the gong 3 times in a row. He knows that after you hit the gong twice, you will lose your concentraton just enough to come up short on the last try.

 

[stirner]

In addition to my first post, you can try the mechaical portion of accuracy. First, remove the receiver screws, leave the bolt in the receiver, and grasp the rifle such that your thumbs are directly above the screw holes. Apply alternating pressure with each hand. If the rifle rocks up and down, you have a pressure point on the receiver that must be identified and removed. I'm not familiar with the stock on that rifle, but if the receiver is not fully bedded, it wouldn't hurt to do so. Devcon is best. Is the scope on tight? Is the barrel free floated?

How about your ammo? Is your case prep and loading procedures adeqaute?

Because your problem is consistently with the last two shots, I believe you have a heat problem, or shooting routine problem. More the latter than the former.

 

[mrjashu]

I would love to see a few pics of exactly how you tackled it. What kind of groups are you getting?

I usually only shoot three shot groups, but it will put three inside .5 MOA without too much difficulty as long as I'm paying attention. That goes for factory 140g ELDM and my own handloads with 143g ELDX

I didn't take any pictures of the bedding process. But basically I used a dremel to grind down any spot that was going to receive epoxy by a few thousandths. I took particular pains to expose the aluminum pillars so they would be well bonded to the bedding. Leave the surfaces scuffed up and rough, clean with acetone then you just bed it like normal.

Here's a couple of groups with Hornady factory match 140g ELDM