New kid on the block

[Smokey_GA]

This is my first thread, I've been removed for muzzleloader hunting for a few years but I decided to get back in last year. I've been having problem after problem getting my rifle to group, and after months of lurking in the shadows of the forums I decided to jump in.
I have a cab accura PR, I've tried 250 and 300 grn. Barnes sabot with multiple weights of bh209 each off of a lead sled but I just can't make it work. One day I'll shoot a 1" group and the next day I'll shoot a 6" group. If anybody has ever had this problem or knows of anything that I might have overlooked I would surely appreciate any advice.

 

[michiganmuzzy]

3 things
1) welcome to the Best ML forum!
2) sounds like you may have a loose scope mount maybe. Take them apart, clean them and blue loctite them back in place.
3) cant remember what 3 was, oh yeah,
Welcome to the forum

 

[Smokey_GA]

I had that happen once before, I thought I'd fixed it but I've been known to be wrong a time or two. Do you or anybody you know know how to break down twist rates? I've heard that a cva won't group well under 300 grains, but a 1:28 twist isn't enough to handle a bullet that long.

 

[michiganmuzzy]

I had a PR Accura not long ago. Its an awesome gun. It will shoot bullets over 300 just fine. They do tend to like a hotter load according to many. The JBM calculator is a good tool to ggive you an idea whether or not a specific bullets going to stabilize and shoot well. You may have something simple like a worn out breech plug or maybe need the Blackhorn loose powder style breech plug.
But that gun will shoot almost anything you can stick down the barrel.
https://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi

 

[michiganmuzzy]

Youve gotta input some info into the JBM cal but once you play with it just a lil it is easy to use. You need bullet caliber, length, weight, muzzle velocity, twist rate and i think thats the minimum info. You can input temp too

 

[Smokey_GA]

I went ahead and bought the breech plug from the get go. For the record, my best groups were with the 300 grn expander mz over 77 grns. I tried the harvester crush ribs to make it a little easier to load and didn't lose accuracy, but my POI dropped about 6". I may try the 290 tez next. What all did you run in yours?

 

[michiganmuzzy]

I went ahead and bought the breech plug from the get go. For the record, my best groups were with the 300 grn expander mz over 77 grns. I tried the harvester crush ribs to make it a little easier to load and didn't lose accuracy, but my POI dropped about 6". I may try the 290 tez next. What all did you run in yours?

I loved the 290TMZ in my PR. Was that 77gr weight or volume measured?
fyi, If youre posting Blackhorn loads on here, always specify if its by Weight or Volume. 100 gr volume is fine but 100gr by weight is way too much in an Accura.

 

[Smokey_GA]

Oh most definitely weighted, I'm too particular for volume measurements

 

[Scotts98rt]

It is not what you're using if it produces 1in. Groups . My bet is base/ring loose. Or bad scope. If the base/rings are tight my advise is use a scope that you know is good, put it on and see if it goes Away.

 

[michiganmuzzy]

Yep. What he said. ☝

 

[michiganmuzzy]

Smokey are you adding weight on to that ledsled? Those things have killed many good scopes.

 

[snapbang]

If youre posting Blackhorn loads on here, always specify if its by Weight or Volume.

Maybe it would be a good idea to adapt a 100(v) or 100(w) type method for all powder measures used on this forum. I dont think all powders come in a pellet form but newbies may not know that. Just an idea.

 

[Smokey_GA]

No I'm not adding weight to it. I came across a thread like that on here a few weeks ago, it may be that even though I'm not adding weight the empty sled is just bumping the reticle.

 

[Valkyrie]

Fwiw, when I'm sorting out a rifle I stick to fifty yards and shoot at the smallest reasonable target dot at that range on a clean target. Usually flipping it to the backside where it's white and clean. Most generally if it won't group tight at 50, it will not come close at 100 yds. Good advice above re the sled and scope. A loose or defective scope will drive you nutz..

 

[Smokey_GA]

That's what I've been doing. Cloverleaf at 50, one inch group at 100, bullets flying everywhere the next day at 150.

 

[Valkyrie]

One inch at 100 is really good. Can't figure the 150 results.

 

[Smokey_GA]

That's what im saying. Barnes bullets cost too much to keep this stuff up

 

[Smokey_GA]

It looks like the lead sled was the problem. Shot 10 times today using 8 leftover Barnes 250 tez x 70 grn(w) and 2 leftover Barnes expander mz 300 x 77grn(w). The 250's weren't my most accurate load but it's what I had on hand but the 300's were touching (black stickers covering 250's, orange stickers marking 300's)

 

[Valkyrie]

Cha-Ching! Glad you figured it out.

 

[michiganmuzzy]

Shoot again tomorrow or in a few days and report back with results. Hope you got'er figured oot. Try them 290s. I felt like they werked better in my PR.