Having trouble getting my 7 LRM to shoot

[Dhughes]

I've tried retumbo and H1000, 168, 180 hunters, 180 hybrids and 162 amaxs, seating from .010 to .050 off the lands and charges from 69-72.5 grains.

Nothing shot any better or any worse really.
I've checked the bedding and torqued everything a couple times. I shot it without the brake to see if it was causing anything. Nothing seems to help.
I also don't know why I had to back off of my loads so much compared to everyone elses?

Thanks for the advice everybody. I'm going to mess with it a little more and if nothing changes, its going back to the smith.

 

[deertroy1]

I feel your pain. I purchased a new Cooper in 7mm-08. Everything I tried seemed to shoot 1.25" - 2.25". I returned the rifle to Cooper and it had an issue with barrel run out. They rebarreled and rebedded it. I got it back and it still doesn't shoot. Tried the scope on my 300 Win Mag and shot 0.58" and 0.72" four shot groups. That ruled out the scope so it's back to Cooper a second time!

 

[IdahoCTD]

Then I would try them again into the lands or within a few thousandths of the lands. If everything else on the rifle checks out ok then it's probably a bad barrel. Bad barrels happen. I've had a bunch of bad ones in the last 20+ years. Send the barrel back to Broughton after the smith once overs the rifle.

 

[Dhughes]

Thats what I'm thinking too. I was wrong on the barrel, its a bartlein not a broughton.

 

[sbruni]

Did you work this out?

 

[Dhughes]

No I never got it going right. I got tired of messing with it and its been sitting ever since. I can't decide wether to put a new barrel on it, or sell it/part it out.

 

[AZShooter]

I hate to say it but if you could put another barrel on it or rechamber the existing one you might be able to figure out why it won't shoot. I am pretty sure a 7 RUM should clean up the chamber without setback.

 

[Jim See]

Your twist rate is pretty fast for the 180's what led to the choice of an 8.4?
Most guys are running 9's This faster twist will in effect cause higher pressure as well.

what barrel contour is on this gun?

 

[Wachsmann]

It's funny that the LRP guys seat the bullets at .080. I have a 6.5 which I seat my bergers at .100 off the lans. It shoots .5 inch groups and the 300RUM is looking like the .070 to .080 is showing to be the best overall seating depth as well also. I think you have to play a little more with the bergers to find the sweet spot for each rifle. My wifes 243 on the other hand has been putting up a fuss with the 95grn bergers I get about 3/4 goups at 100yrds. It will shoot some of the silver tip factory ammo about .5. So I'm going to try something different for her rifle. I hope yours works out. I will be tring some 168 and 180 in a 7mm mag soon.

 

[cohunter14]

A couple of questions for you:

1) Is the barrel free floated and is there a good amount of clearance? Just by looking at your targets, it looked like most times shots 1 and 2 grouped 1/2" or less and then shot 3 would be a flier. Could the barrel be heating up and contacting the stock somewhere?

2) Did you ever take it back to your smith to get his thoughts? I would think he might be able to help out.

 

[Dhughes]

The barrel contour is a remington varmint. I tried the bullets in the lands to way off the lands and it never really changed any. The only way that I got it to shoot any better was if I slowed it down to about 2700-2800 fps.
The barrel is free floated. That was the first thing I checked.
I took it back to the gunsmith and he cut the brake off and recrowned it to see if that was the problem. It wasn't. I then took it back to him with dies, brass, bullets and powder because he said he would work with it. It set in his shop without moving for 3 weeks or more, so I went and got it.
I had a mule deer hunt coming up, which is what I built the gun for, and didn't have time to mess with it anymore. Its been leaning up in the corner ever since.

 

[Augustus]

Dhughes, wait until you have three or four of these dogs sitting around. I could write a book on high dollar custom rifles that won't shoot. My experience with custom rifles has left a lot to be desired. I once sent a Nesika action, Broughton barrel and a Mcmillian stock to a very well known gunsmith. It came back minus a bolt, the bolt was never found. After months of haggling over whose fault it was I bought a new bolt and had it redone. The rifle was sent to this gunsmith because it was shooting around 2moa after being built by another very well known smithy using a Hart barrel.

I had an AR built by another very well known smith. I started breaking the barrel in and started having head separations, turns out the headspace was off by a mile.

I bought a brake and had it installed on a 300 Ultra by the same smith, after 600 rds the gills blowed out while sitting at a bench shooting with two friends. Thankfully the flying hunks of metal didn't hit them.

I bought a custom action that came with no bolt catch and the trigger pin holes were off so far I could not install the trigger.

I bought a custom built base and had it installed by a very very well known smith, it was supposed to be pinned to the receiver. The rifle shot like crap when I got it back. The front screw was over length and was torqued down on the barrel threads, the screws were oval heads but the base was cut for fillet heads. The base was so far out of spec that no rings I tried would work and the base had not been pinned.

I can go on but I think you get the drift.

 

[Moe Curls]

Don't Give Up!

It finally came together. After 170 different combinations of powder, seating depths and primers I have an acceptable load.



I am attempting to shoot Berger 168 gr VLDs. Based on the reported velocities of the 180 VLDs I hoped to get 3300 fps with the 168s.

We have been experiencing the same frustration as others have mentioned. We have had nine range sessions so far. We had been getting bizarre results with the recommended powders at or near max loads. These same powders have worked great in other similar calibers.

In trying to figure out the crazy results we questioned everything that could possibly contribute to the poor groups. Barrel--bore scoped twice. Bedding--checked and redone.
Crown--checked and redone. Bolts and screws checked and confirmed to spec. Scope--removed and replaced.

The rifle was shot with a clean bore. The rifle was shot with a fouled bore.

The rifle was shot with the muzzle break on. The rifle was shot with the muzzle break off.

The rifle was shot by different shooters. The other calibers being shot during the same range sessions were doing fine.

Next we thought it might be neck tension. Neck tension was correct.

Brass needs to be full length resized after 3 firings. Necks are resized with a custom neck bushing die.

Brass concentricity and bullet run out. Not good. Brass out up to .005
Now the brass is being culled and indexed. Results start to improve but we are still experiencing crazy ES near max loads.

Finally we decide to back the load way down to see if things would improve. We had experienced the best groups previously (3/4" group) with 4831sc but not great velocity.
We gave up on the velocity we hoped for. With 4831sc the ES for 4shots was 8fps. Velocity at 3100 fps

The groups came together.

I know the cartridge was designed to shoot the 180 gr VLD

In conclusion, it is my opinion (as mentioned in a previous post) that the brass is very soft and easily deformed near max pressure and this may be contributing to the problems.

We will be back at the range tomorrow with two new powders to see if we can improve on the group pictured and start load development on the 180's. Just for fun, we have a few 140 gr VLDs to try.

 

[eshorebwhntr]

I believe the first post said he was using Hybrid's. Per Bryan Litz, they shoot as good .010 from the lands as they do .060 from the lands. The results out of my 7 STW echoed this.

If you're hitting pressure earlier than you think you may have a tight chamber or a rough cut chamber with a dull reamer or a reamer that wasn't run smoothly. However, if it was cut true the accuracy probably wouldn't be a problem. Some of your loads look like they have a good bit of vertical stringing...what is the chrono reading? Does it back up the stringing issue? If you have <75 fps ES and are still getting groups like that at 100 yards something is likely misaligned in the action and needs to be reworked.

imho if the rifle was built right you shouldn't have to spend as much time as you have to get into the sub moa range. I don't know when your deer hunt is but you might want to be looking for another smith quickly. I highly recommend Greg Tannel of Gre'Tan Rifles. I have 3 built by him and they all shoot great and are very tolerant of different loads and bullet brands. Another member recommended the RUM to save the barrel if the chamber is re-cut...not a bad idea. I would throw the STW out there as a possibility as well.

Good luck in whatever direction you go. Hope you get something worked out for your deer hunt.