At the bench5 min read
My rifle won’t group: where to start
Start with the cheap things. Loose screws and scope mounts cause more misses than bad barrels, and you can check most of them at your kitchen table.
A rifle that used to shoot and now doesn’t is nearly always telling you about something small. Most of the rifles that come to a gunsmith’s bench for “accuracy work” need a screwdriver, not a lathe. Here is the order to check things in, cheapest first. You can do nearly all of it yourself.
One rule before you start: change one thing at a time, and write down what you changed. If you change three things and the rifle improves, you have learned nothing.
1. What changed?
Ask this first. A new box of ammunition, even the same brand in a different lot? A new scope? A trip in the back of the truck? A wet week? Rifles don’t go bad on their own. Something moved.
2. Ammunition
Rifles are particular. One will shoot a 150-grain load into a tight cluster and scatter a 165-grain load from the same maker. Before you blame the rifle, try two or three different factory loads. Shoot three groups of each, not one. A single good group is luck until it happens again.
3. Action screws
These are the screws under the stock that hold the action down. If they are loose, or tight at one end and slack at the other, the action shifts a little with every shot. Wood stocks swell and shrink with the weather, so screws that were right in August may not be right in November.
Check them with a torque wrench if you have one, to the figure your rifle’s maker gives. If you don’t have one, snug and even is far better than loose. Don’t lean on them. A crushed stock is its own problem.
4. Scope bases and rings
This is the most common fault of all. People check the ring screws because they can see them. The base screws, underneath the scope, are the ones that work loose.
Take the scope off if you have to. Check that each base screw is tight. Put the rings back and tighten them evenly, a little at a time, crossing from side to side, to the ring maker’s figure. It is less than you think, and a crushed tube can’t be fixed. Then put a small pencil mark on the scope tube at the edge of a ring. If the mark has moved after twenty rounds, the scope is slipping.
5. The scope itself
Scopes fail more often than barrels do. If you have another one you trust, swap it on and shoot again. If the groups come back, you have your answer and it cost you nothing.
6. Clean it properly
A bore caked with copper will open up groups. Clean from the breech, with a bore guide and a one-piece rod, until the patches stop coming out blue-green. A bronze brush will turn a patch blue by itself, so judge by a patch on a plastic or nickel jag. Then shoot three or four fouling shots before you judge it. Many rifles won’t settle until the bore has a little fouling back in it.
Never clean from the muzzle if you can help it. That is how crowns get worn.
7. Look at the crown
The crown is the very end of the barrel, the last thing the bullet touches. Push a cotton swab out through the muzzle and draw it back across the edge of the bore. If fibers snag, there is a burr. A nick you can see with a magnifying glass is enough to matter.
This is the first item on the list you can’t fix at home. It is also a small job.
8. The barrel channel
Many modern bolt rifles are made with the barrel free of the stock ahead of the action; others are made with a pressure point near the forend tip on purpose, and lever guns and full-stocked rifles are not floated at all. Find out which yours is before you judge it. On a floated rifle a strip of paper should slide from the tip back to within an inch or two of the receiver. What you are looking for is contact the maker didn’t intend: the stock touching on one side, or touching only when the wood has swelled. Don’t sand anything yet.
9. The bench and the shooter
Be honest about this one. Shoot from a solid rest at the front and a bag at the rear. Hold the rifle the same way every shot. Let the barrel cool between groups; a thin hunting barrel walks as it heats. Shoot on a calm morning if you can.
When to bring it in
If you have been through all nine and it still won’t group, the rifle likely needs bedding or a fresh crown; a cleaner trigger helps the shooter more than the rifle; and on a rifle that has been shot a great deal, the throat may simply be worn. Machine work on the barrel or action comes last, and only if the rest hasn’t done it.
Bring your notes. They will save an hour of diagnosis, and they will tell a gunsmith more than the rifle can.
General guidance, not a substitute for your firearm’s manual or a gunsmith’s inspection.