Help me shrink my group size....

[gltaylor]

@Koda ,
You've more or less done the basics, but some refining and tweaking may help in your loads:
1st: Stay well away from the lands. Most start at least 0.20 off of "jam" with bullet/rifling contact.
2nd: work up to pressure going up 1/2-1grain in powder depending upon cartridge size 1/2 gr in 308 and smaller cases. For magnums, 1 gr steps is good.
3rd: once you find pressure, back off 1 full grain for a safety margin (higher temps may push you toward/closer to pressure.
4th: if you're going to crimp, start with 1/8th crimp (then you can go up in your testing if needed.)
5th: if you start with a crimp, adding more does not appear to materially affect either velocity or pressure. The most I've personally noted is a 20 fps change.
6th: changing seating depth typically has very little if any affect. Most of your tuning a load will be done with powder changes. 2 tenths gr can have remarkable affects.
7th: when you get down to 1" or less groups, final tuning can be done by changing primer brands (stay with same strength...ie LR or LRM). Don't switch LR to LRM.
8th: final tuning is by changing crimp amounts incrementally. My personal process is 3 round groups at 1/8th, 2/8, 3/8, etc to 1/2 turn crimps. When crimping, move your bullet so you can crimp INTO a PDR band. Typically, changing crimp setting will clearly show a specific preference. It is not uncommon to find a crimp setting that is 0.5 better than the rest.

In all of this there are several assumptions:
1. You have a case fill of at least 85% powder where you find pressure. If this is not the case, you need to change your powder burn rate (choose another powder)
2. You've verified your various screw torque settings and scope
3. Your barrel is well cleaned of fouling and carbon
4. A last and only occasional tweak is adding fore end pressure (especially if you shoot a "noodle" barrel. Fore end pressure rately affects barrels at .725 muzzle OD or heavier.)

 

[littlebighorn]

Lots of great suggestions here.
I would add checking scope, especially on the 280ai for loose screws, and also look at the lug action screw tension. Maybe even play with more or less tension.

 

[jrebel]

The only times I have found hammers to not shoot well.

1. A buddy’s custom 300rum that was not bedded properly. Wouldn’t hold less than a 3 MOA group.

2. To heavy a hammer for the twist. I thought I could make it work and…..I couldn’t.

3. The powder was the wrong powder for the load.

4. The shooter wasn’t able of holding a good MOA.

In my process of reloading hammers, if my ladder test does not group well, I switch powders.

I have yet to see a crimp improve a 2 moa group to a sub MOA group. Crimp will make a 1 MOA group 3/4 or 1/2, so I use crimp to fine toon loads. Point being…it will help, but likely will not turn your 1.5 MOA to a 1/2 MOA.

Peterson brass is some of the best brass on the market. When you switched to it, did you rework your ladder / pressure test? If not, I would start there. Nosler is good brass….peterson is better brass, don’t go backwards.

Seating depth is not or at least should not be an issue. All my hammers like to jump.

This brings us to a couple things I would consider.

1. Re work a pressure / ladder test. See how it groups. If it doesn’t group well (meaning your rounds are all over the target (larger than 2-2.5 MOA) go to a different powder and repeat.

2. Have a friend shoot your rifle and see how it groups with a different shooter.

I should also mention….check your torque specs on your action screws, scope base and scope rings. Improperly torqued screws can be a big problem and you can never trust factory torqued screws.

 

[BFD]

Send me the rifle, dies, 145HHTs (I have 132HHTs) unloaded, but primed brass, and I will have it figured out real quick and report back to you my findings and recommendations.

 

[les]

Koda - I'd take BFD up on his offer. Second, I wouldn't trust the advertised twist rate on that Browning. Getting an evaluation from your local gunsmith would cost you more than sending it to Koda. Last it is hard to find a good gunsmith these days and if you do they are very busy.

 

[fuzzymarindave]

Peterson brass is some of the best brass on the market. When you switched to it, did you rework your ladder / pressure test? If not, I would start there. Nosler is good brass….peterson is better brass, don’t go backwards.

On my 280 AI I switched from Nosler brass to Peterson brass and found the Pederson to be heavier in weight and requiring a lower powder charge compared to Nosler brass. Although the 3200 fps for the 140 gr AH doesn't stand out as too high.

Technique- If the x-bolt is a lightweight rifle consider adding a folded bipod to use the extra weight to help mitigate muzzle jump from recoil. Just maintain inch or two clearance between the bipod/sling swivel and the front bag to allow rifle to slide back under recoil. Trying for consistency. This technique helped me shrink groups on my 280 AI lightweight rig.

 

[Koda]

BFD: Shipping it out is a very generous offer I am truly thankful for the friendship offered here. I would like to figure this out to learn myself, Im good with this rifle out to 400 well within most ranges I hunt out here, I just know I can improve this. But this is still a very accurate usable rifle for me even as is.

A comment in another thread also on grouping gave me an epiphany, my stocks recoil pad on the 280ai is incredibly thick and super soft. Its a cheap plastic factory stock but I like the stock otherwise but have always wondered about the pad, its like over an inch thick and all squish. It could be causing movement during recoil?


To follow up on some other questions everything's tight and properly torqued on the gun, rings, mount, stock screws. The stock is very tightly bedded, the barrel is fully floated. I did take the stock off last night and can see now why Browning doesn't suggest to remove it, its very very tightly bedded and the bedding material "seems" kinda soft to me. I had to be super super careful putting back together not to scrape the bedding with the recoil lug and to me it seems like every time the stock is removed its only going to loosen up the lug pocket. My guess is in production, they squirt the epoxy on the stock, assemble the rifle and call it good. A perfect fit, low cost production. It doesn't seem like anything in there would need cleaning but its still odd the idea of never cleaning there. I blew out some pine needles down there and minor debris from last falls hunt. It got rained on hard several days but all was dry and no rust but still.

Screenshot below of the stocks recoil pad, its like over an inch thick and all squish. Detail of the soft epoxy bedding.

 

[Koda]

On my 280 AI I switched from Nosler brass to Peterson brass and found the Pederson to be heavier in weight and requiring a lower powder charge compared to Nosler brass. Although the 3200 fps for the 140 gr AH doesn't stand out as too high.

I found the same exact thing.
I weight water weight of the two and calculated the percentage difference and noted that on my Noslers charge weight. I still ran a new pressure ladder on the Peterson brass around the difference and found pressure virtually at the same percentage difference in charge weight as the case fill.

In both cases I got a sticky extraction sign for pressure, a slight swipe mark on the side of the case head. I dont know if its a false pressure sign from a burr in the chamber, but Ive always thought that 3200 was low for this Absolute from a 26in bbl.

Edit: after finding my journal notes I did not get a sticky extraction with the Peterson brass but got a faint extractor mark as its first sign of pressure. It looks like I backed off only .3gn which is odd for me but again Ive always thought that 3200 was low for this Absolute from a 26in bbl. so maybe I was trying to chase velocity. No matter how detailed I try to keep notes its always hard to revisit them later

 

[jrebel]

Are you cleaning the brass of all lube before shooting. Usually a sticky extraction is due to not have lube cleaned off the brass. Also make sure the chamber is cleaned of all lube.

 

[les]

I think you would be amazed by changing out that recoil pad. I personally like the Pachmayr Decelerator pads.

 

[Koda]

Are you cleaning the brass of all lube before shooting. Usually a sticky extraction is due to not have lube cleaned off the brass. Also make sure the chamber is cleaned of all lube.

yes, and yes.
Heres a pic of the sticky extraction swipe. Nosler brass. The "stickiness" is just a slight feel on extraction not a sticky or heavy bolt lift. Bolt lift is easy and smooth. It makes me wonder if its just a high or rough spot in the chamber but I decided not to ignore it.

 

[Koda]

I think you would be amazed by changing out that recoil pad. I personally like the Pachmayr Decelerator pads.

The recoil pad does not look serviceable, but I will have to look closer when its out of the safe next as Id rather not have to buy a whole new stock right now. It looks glued on to me.
Im suspecting this is a question I should eliminate before I do any (expensive) load refinement...

 

[les]

That primer looks really good! No pressure signs.

 

[Koda]

That primer looks really good! No pressure signs.

yes. Overall I was very happy with the Nosler brass grouping but its velocity was even a bit lower. Ive had lots of quality issues with Nosler brass in another caliber and in 280ai had to do extra work to prep the brass neck rim would always fireform very inconsistent.
When I finally found some Peterson brass, I found every measurement the same including case weight... compared to the Nosler.

 

[Koda]

So I can remove my recoil pad, Browning uses their "Inflex" recoil pad on my rifle. The design makes it slide the butt of the rifle stock down away from the cheek weld on recoil for faster followup shots.
This seems like a bad idea to me as I would think I dont want my stock moving vertically under recoil but only straight back? Maybe some of the more experienced long range shooters here can confirm?

Theres a simple Pachmeyer recoil pad on Midway Im looking at. I feel like I should eliminate this question of the squishy recoil pad before I try to tune handloads.

Pachmayr D750B Decelerator Field Style Recoil Pad Grind to Fit

The D750B Decelerator Field Style pad delivers dramatic recoil reduction with a basket weave finish and a shape that is ideal for heavy recoiling...

www.midwayusa.com

 

[Ddubs20]

I second the idea of shooting a powder ladder test. Once I know the upper limit i back off and shoot 2 shot groups in .5 grain increments up to near max. In my 7mm mag with the 140 AH i found excellent accuracy but only at certain small powder windows. Best of luck!

 

[choprzrul]

BFD: Shipping it out is a very generous offer I am truly thankful for the friendship offered here. I would like to figure this out to learn myself, Im good with this rifle out to 400 well within most ranges I hunt out here, I just know I can improve this. But this is still a very accurate usable rifle for me


To follow up on some other questions everything's tight and properly torqued on the gun, rings, mount, stock screws. The stock is very tightly bedded, the barrel is fully floated. I did take the stock off last night and can see now why Browning doesn't suggest to remove it, its very very tightly bedded and the bedding material "seems" kinda soft to me. I had to be super super careful putting back together not to scrape the bedding with the recoil lug and to me it seems like every time the stock is removed its only going to loosen up the lug pocket. My guess is in production, they squirt the epoxy on the stock, assemble the rifle and call it good. A perfect fit, low cost production. It doesn't seem like anything in there would need cleaning but its still odd the idea of never cleaning there. I blew out some pine needles down there and minor debris from last falls hunt. It got rained on hard several days but all was dry and no rust but still.

Screenshot below of the stocks recoil pad, its like over an inch thick and all squish. Detail of the soft epoxy bedding.
View attachment 6027

I once had an X-Bolt that I fought accuracy with….it just didn’t seem like it was shooting up to its potential. It too had that soft squishy bedding material.

On a wild hair, I went to the auto parts store and bought some plastigage ( the stuff engine builders use to check main bearing clearance). Lo and behold, that factory bedding had a gap of .003-.005”+ in most places.

A trip to my gunsmith friend and a proper bedding job brought that rifle into the sub MOA arena. Not saying this is your problem, only what I found and worked for me on that rifle.

My new X-Bolt 270 WSM shot great right out of the box with only the MCarbo trigger spring and some 122gr HHT (0.4” group at 3373 fps).

 

[hand skills]

Would it be beneficial to ask a random stranger at my range? I have only 3 friends that hunt, let alone shoot rifle. Im sort of on my own, with anything handloading and shooting.

If a random stranger is printing sub-half moa groups with a hunting weight rifle, absolutely!

Without qualification, however, it will tell you nothing.

I'd take @BFD up on his offer - pretty good chance the gun will come back with a good load, then the rest is up to you!

 

[fuzzymarindave]

So I can remove my recoil pad, Browning uses their "Inflex" recoil pad on my rifle. The design makes it slide the butt of the rifle stock down away from the cheek weld on recoil for faster followup shots.
This seems like a bad idea to me as I would think I dont want my stock moving vertically under recoil but only straight back? Maybe some of the more experienced long range shooters here can confirm?

Theres a simple Pachmeyer recoil pad on Midway Im looking at. I feel like I should eliminate this question of the squishy recoil pad before I try to tune handloads.

Pachmayr D750B Decelerator Field Style Recoil Pad Grind to Fit

The D750B Decelerator Field Style pad delivers dramatic recoil reduction with a basket weave finish and a shape that is ideal for heavy recoiling...

www.midwayusa.com

Koda. I’m going to suggest there is nothing wrong with the Inflex recoil pad. The factory bedding job is a maybe. I have two x-bolts and they are my only rifles that I have not done a custom epoxy bedding on (excepting a Savage composite stock with internal aluminum chassis). Both x-bolts shoot under 1 MOA although they do have the “pro” carbon stock so I have no experience with composite stock. Their factory bedding looks like yours.

Another technique to try- load up magazine and shoot your 4 or 5 shot group without moving from your shooting position. Sit there quietly while barrel cools for your normal cooling duration. After each shot eject empty but leave bolt open until ready for next shot. By doing this you may eliminate some shooter/rest variables and shrink your group.

 

[fuzzymarindave]

Koda. I’m going to suggest there is nothing wrong with the Inflex recoil pad. The factory bedding job is a maybe. I have two x-bolts and they are my only rifles that I have not done a custom epoxy bedding on (excepting a Savage composite stock with internal aluminum chassis). Both x-bolts shoot under 1 MOA although they do have the “pro” carbon stock so I have no experience with composite stock. Their factory bedding looks like yours.

Another technique to try- load up magazine and shoot your 4 or 5 shot group without moving from your shooting position. Sit there quietly while barrel cools for your normal cooling duration. After each shot eject empty but leave bolt open until ready for next shot. By doing this you may eliminate some shooter/rest variables and shrink your group.

Just today I had some flyers which I attribute to me not consistently settling behind the gun. I have a habit of standing up and walking around after each shot. I take notes, let barrel cool, etc. Each time I sit down for the next shot there is risk of changed position (cheek weld, rear bag pressure, etc.). Here are three 200 yard groups with a factory x-bolt; each showing a flyer. The flyer is certainly me. I need to stay on the bench until the group is finished.