6.5x55 155gr Lapua mega load

[nuke-cu]

I would like to post a big game load that seems to work well in my CZ 550 6.5x55 Swedish mauser. My CZ has a long throat and my experimenting has been with 140 gr Sierra Gameking and 155 gr Lapua mega. I have had better luck with Lapua loaded to COL 3.020" (0.040" - 0.045" off of the lands)

155 gr Lapua Mega, 45 grains RL 22, Lapua brass, Federal 210M primer. This load has very load SD - as low as 3 fps. It does show a little horizontal stringing - probably me pulling it. 1.8" - 2.5" at 200 yards.

If I increase the charge by 0.5 grains: 155 gr Lapua Mega, 45.5 grains RL 22, Lapua brass, Federal 210M primer, I get a little vertical stringing and groups. 1.6" - 2.5" at 200 yards. I actually had 4 holes touching (0.6" CTC) and a 5th one at 2.5".

My guess is that 45.2 gr RL 22 will be good. I could not confirm this today since my performance was not good but I got more credible chronograph data and it clocked at 2610 fps. If you have a modern rifle in the Sweedish mauser caliber you may give this combination a try (especially if you have CZ 550).

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This load comes with a question. My original 45 gr and 45.5 gr loads clocked at ~
2710 fps and 2740 fps. I have recorder every shot (2 5 shot groups each). Today the 45.2 gr RL 22 clocked at 2610, which is much more in line with the performance of the Swedish mauser. I believe this is the correct muzzle velocity but I cannot understand what will cause the original anomalously high results. Have you had a similar experience? I have the F-1 chrony.

Thanks.

 

[SJB358]

It could be lighting or just the way the bullet crosses the chrono. Not totally sure. Could be a different lot of powder as well..

Either way, I am thinking that big Lapua Mega is a cool bullet. I have looked at them in the past and they look like very suitable big game bullets and the SD on them, well it has to have excellent penetration. Throw a picture or two up. Scotty

 

[Antelope_Sniper]

Nuke, might want to try some H-4831 in that sweed.
Real consistant in mine.

 

[nuke-cu]

Here are a few groups at 200 yards. I don't have a loaded round. I will add a picture later.

 

[Oldtrader3]

Your load appears to be somewhat bimodal with two almost separate but small groups. Is your rifle barrel bedded or free floating. I am asking because it could be a bedding issue with the stock or even a scope issue? Just thinking out loud?

 

[nuke-cu]

The barrel is free floated. There is very little bedding compound in at the two edges of the recoil lug. (I don't consider this bedding). It is stock CZ 550 with the trigger adjusted by me. I cut an 11 degree crown using a Dave Manson cutting tool.

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Let me add that I consider any spread add/or pull in 3 of the 4 groups result of my limited ability as a shooter. It will take much more work for me to get better groups at 200 yards.

 

[1Shot]

I will pass on a little trick I stumbled onto while fooling around with old military rifles that have long throats. Use a Lee Factory Crimp Die to crimp the case to the bullet. You don't need a crimp groove on the bullet to use the Lee Factory Crimp Die because it makes it's own. I have seen greatly improved accuracy between rounds crimped and those not crimped. Don't be skeptical and think that using this die will harm the bullet and make it not fly good. I have heard it all from the fellows that I shoot military rifle bench rest matches against. I just keep winning matches for some reason with those "ruined match bullets" :mrgreen: . Funny thing is that a couple of the fellows started listening to me and started using the die on their ammo and their scores have really gotten better.
My theory is that it is not bullet jump that is the problem with accuracy it is a pressure problem. The crimp holds the bullet in the case for that moment it needs to build the pressure up to get a good burn going on the powder much like a bullet that is loaded close to the lands will be retarded a moment when it hits the lands before the bullet leaves the case.

Another tip: Leave your cases 5 thousands longer than the trim to length. This will give you enough case to get a good crimp on.

I have always had best accuracy and great velocity with hunting loads 120 and 140 gr bullets with Accurate Arms 4350 in my 6.5 Swedes.

 

[nuke-cu]

Thanks for the tip! I have read that this is how factory ammunition achieves good performance in a variety of rifles. I may give it a try, I use Lee dies anyway.

 

[nuke-cu]

A couple of pictures for comparison. 155 gr Lapua mega on the left; 140 gr Sierra gameking on the right.

 

[SJB358]

Man, those Mega's look like some cool bullets and at 155gr's should be really something in your 6.5. I would like to try something heavy like that in the 264. Might be interesting to see what they do. I imagine 3000 is still possible with them, especially with a decent load of Retumbo. They look pretty deadly with that FP on the front.

You would be the first to show us some Mega's recovered from anything were you to shoot them into some media. I would be interested to see what they look like. Scotty :lol:

 

[nuke-cu]

I haven't really tested performance or shot anything (other than paper) with them. I plan to this fall, if I am successful. There is an excellent thread on on of the internet forums, I think by a guy by the name Steve. I think the forum is 24hourcampfire. It requires some googling to find the thread (I don't have the link right now) but if you find it it is one of the most informative threads on bullet performance. He tested many 6.5 mm bullets and Lapua mega gave performance very similar to Nosler Partition.

 

[FOTIS]

have you tried 3 shot groups? The barrel might be getting hot.

 

[SJB358]

I haven't really tested performance or shot anything (other than paper) with them. I plan to this fall, if I am successful. There is an excellent thread on on of the internet forums, I think by a guy by the name Steve. I think the forum is 24hourcampfire. It requires some googling to find the thread (I don't have the link right now) but if you find it it is one of the most informative threads on bullet performance. He tested many 6.5 mm bullets and Lapua mega gave performance very similar to Nosler Partition.

I will have to check them out. Pretty reasonably priced bullets as well, and being a Lapua, I would think they are well made and pretty accurate to boot. Looking forward to seeing what they do for you. I tried to look up Lapua load data for the 264WM using them, but no luck. I could always run some 160 data and work up to it. Scotty

 

[Ridge_Runner]

IME the group within a group syndrone is almost a sure sign that the rifle needs the seating depth adjusted.
RR

 

[baltz526]

Lyman has data on the 160gr hornady round nose 160gr. fed 210 primers, 2.785" oal, Max load is listed at 46gr RX22, 2361fps. Test rifle is a 24" M38 military mauser. It seems from this data your load is in the moderate range for your modern rifle.

 

[nuke-cu]

Thanks for the load data. I have the Lyman manual. I think their quoted velocities are really on the low side. With 45.2 gr RL 22 I have now converged to 2620 - 2650 fps (depending on the day, how I set up the chronograph, etc.) I consider this plenty fast for 155gr bullet out of a Swedish mauser. I have shot all the way up to 47 gr but pressure signs develop.

 

[gerry]

Thats pretty good speed for a 155 in a 6.5x55.

 

[JD338]

That 155 gr Lapus Mega should penetrate into tomorrow.
I agree with Ridge, adjust your seating depth. Fotis also has a valid point, shoot 3 shot groups.

JD338