Xtreme Heavy Plate Bullets and AET barrel

[arnettcw1]

I have an SVI with an AET barrel. It will shoot MG 180 HP extremely accurately, but will keyhole about 1 or 2 in 5 Xtreme RNFP's and produce large groups. I have tried different crimps, lengths, powder, etc. and can't seem to get the accuracy to improve with the "regular" Xtremes. Has anyone tried the Xtreme HPCB (heavy plate concave base) bullets in an AET barrel and gotten equivalent accuracy to a jacketed bullet? I would like to shoot the Xtremes because there are about 4 cents less. Thanks.

[craigsteffek]

I have an svi with an aet and I shoot the 180 jhp from xtreme they group ok not as good as mg but around 4 inches at 20 yards

[arnettcw1]

Craig,

Thanks for the reply. My svi will shoot the 180 xtremes with marginal accuracy, but not nearly as well as the MG's as well. I was just hoping someone had tried the HPCB version of the xtremes in an AET. My thinking is that the heavier plating may give the bullet more jacket-like performance closer to the MG and would only cost about 1 cent more than a regular xtreme versus 4 or 5 cents more for the MG. It looks like I just need to order a 250 pack and try it out. I am also thinking of trying some Zero's as they are less costly as well.

[Adam B]

The last AET barrel I had would not shoot moly, lead or plated bullets well at all. It was a tack drive with jacket bullets, there is something about the plating that causes it to not shoot anything other than jacketed bullets poorly.

[Aric]

My aet barrels will not group well with extreme plated. I tried different crimps, over all lengths, 165 and 180s, and different powders with no success. 1 in 10 goes through the target side ways. They aren't even good enough to practice with.

Lead, Polly coat and jacketed are very accurate.

Having said all that, extreme plated shoot great in my standard twist barrels.

[philimandias]

I experienced a similar problem with Berry's plated bullets in my .40 S&W SVI Infinity AET-barrel : the plated bullets go anywhere; but FMJ's are extremely accurate.

[arnettcw1]

Just an update, I tried the Xtreme Heavy Plate Concave Base bullets this weekend. Slightly better groupings and less key-holing than regular Xtremes, but still not what I had hoped for. Looks like jacketed bullets for the SVI. Thanks for all replies.

[candiru]

Just an update, I tried the Xtreme Heavy Plate Concave Base bullets this weekend. Slightly better groupings and less key-holing than regular Xtremes, but still not what I had hoped for. Looks like jacketed bullets for the SVI. Thanks for all replies.

It's the AET barrels. FWIW, the SVI non-AET barrel that I have shoots the Xtreme HPCB's quite nicely -- performs well in my (unscientific) heads up comparisons against the MG and Zero JHPs.

[hotrodder]

I have an older SV with the Schuman AET barrel that has about 60,000 rounds thru it. It is still quite accurate with the MG 180,s. I tried the Xtreme 180 and they tumbled so bad the holes were 1" slots cut in the target. My normal load is ramshot competition 4.6 gr @ 1.185 oal. I loaded up some Xtreme 165 to try with 5.1 gr. of competition and had a 5 shot group of 1-1/2" at about 18 yards with nice round holes! I am wondering if the lighter bullet traveling faster puts a better spin on the bullet for increased accuracy. I have since loaded up 50 each 165 flat points and hollow points for further testing for accuracy and chrono.

[EngineerEli]

If I recall correctly, the AET barrels have changed over time. I had my AET barrel replaced in my SVI a few years ago, and when talking to them they explained that some of the older versions of the AET barrels didn't respond well to plated or coated bullets, but there most recently manufactured barrels have a slightly different rifling profile, and they work much better. I shoot coated lead out of mine and it's plenty accurate for our sport. May want to place a call to SVI depending on when you think the manufacture date of your barrel was...

[Guy Neill]

I'm going to guess a bit and say that some of the problems may be the gain twist of the barrel (at least I understand the AET barrels are gain twist. This means the bullet is traveling much faster when the barrel tries to impart the final spin to the bullet. With the softer plating, versus harder jackets, the bullet may have problems by skidding through the first portion of the faster twist portion of the rifling. Has anyone noted heavier fouling in the front (faster twist) portion of the barrel - or examined any recovered bullets?

This is speculation, but Schuemann's website says the bullet reached 80 - 90 % of it's final velocity in the first 1 to 2 inches of travel.

Just sort of thinking out loud, so to speak. It would be interesting to run tests and recover bullets to see what they look like as velocity increases with a variety of bullet types.

Guy

[3djedi]

I use the 180g xtreme HP's in the Apeiro with AET barrel. When I first tried them I was getting some keyholing. Maybe 1 out of 10. I changed the crimp and the OAL and now they are plenty accurate for USPSA. MG's are better but the xtreme's are definitely good enough for practice.

I ran a classifier in a match last weekend. A standard USPSA target at 35 yards. Two strings of 6 rounds at the 35 yard target (and 6 rounds strong/weakhand at a closer target). I think I got 11 A's using the AET barrel and the Xtreme HP's. I thought that was pretty good. I usually don't do anything past 25 and I tend to choke under match pressure. lol

I do see tighter groups with my DVC when shooting at 25 yards in practice over the Apeiro w/AET.

Edited July 19, 2015 by 3djedi

[arnettcw1]

3djedi,

Thanks for the reply. What crimp and OAL did you end up at to get the improved accuracy? I am at 1.18 and about .420-.421 on the crimp.

[3djedi]

3djedi,

Thanks for the reply. What crimp and OAL did you end up at to get the improved accuracy? I am at 1.18 and about .420-.421 on the crimp.

I believe it is 1.18" with the crimp @ .423.

Sent from my LG-D850 using Tapatalk

[arnettcw1]

Thank you. I will try easing up on the crimp and see if this helps. In the past, I have noticed bullet set-back when I have a crimp much more than .421, but I will definitely give it a try.

[jstagn]

Late model AET 5.4 SVI 200gr. blue bullets clays/claydot/E-3 and others. NO tumbling. OAL 1.208 crimp .420 (.421 max). Good (better than me) accuracy for USPSA.

[3djedi]

Update: I put the apeiro on a rest and shot 180g xtreme HP's, Precision coated lead 180g, and MG JHP's......... I was rather disappointed. Probably good enough for USPSA though

180g xtreme HP's (25 yards) 2.75" (must of been some luck here!)

180g precision coated 4.0"

180g MG JHP 4.0" (WTF)

Also tried my Sti DVC with non-AET barrel

xtreme 2.00"

MG JHP 2.50"

Precision 2.165"

Then I did 25 yards standing off hand

APeiro

---------

xtremes 4.0"

MG JHP 4.5"

precision 4.0"

DVC

--------

xtremes 3.25"

MG JHP 1.65" (lucky?)

precision 2.5"

Interesting to note that my groups with the Apeiro rested and offhand are nearly the same! (I'm terrible at bench resting) Also note that the DVC with a NON-AET barrel produced better groups with all bullet types. WTF?

[3djedi]

Out of curiosity what brand, weight, and type of FMJ's are you guys using? Might be useful to mention powder, OAL, etc. as well

I was using MG JHP's 180g @ 1.18" with 4.7g titegroup.

[GForceLizard]

My AET (May 2013) shoots plated and coated bullets well enough. I use Zero bullets when I care about the increased accuracy. I had a standard barrel fitted last fall for $410 plus shipping. I still run the AET almost all the time.

[hotrodder]

Update, well I put a new infinity non AET barrel in my gun this week. Shot groups at 20 yards offhand with extreme plated 180fp,180hp,165fp,165hp,MG180hp and precision coated185. All loads were 1.195 OAL using ramshot competition at 168 pf. The precision was the best at 2.25", followed by the MG at 2.6". All the extremes were 2.75" to 3". I must confess I really liked the feel of the 165's. I am running a 12.5 variable recoil spring with one aluma buff. I am going to try some more of the 165's in the 170-172 pf range next to see if the accuracy gets a little better.

[whitea87]

Xtreme 200gr. Tumble in my aet barrel as well. Swaped to bayous and never had a single keyhole since.

[pries81]

I had a 6" AET in a custom STI. I shot Rainier Ballistics plated FP 1.18 COL, with .421 crimp. They were extremely accurate (well, for my shooting that is) 1.5 inches at 25 off a bag. I wonder if the Rainiers have thinner playing? Did the barrel being 6" have anything to do with it?

Good thread!

[z40acp]

What about trying some Everglades jacketed bullets. They are $289 a case of 2500 compared to Montana Golds $350.

[Aric]

The xtreme plated tumbled in both 5 and 6" AET barreled guns.

Extreme planted are appealing based on their cost. They are only slightly more than coated lead.

Also, not all of them tumble. Enough tumble, for me, to make them unusable in a match. I have had the tumbles called doubles and shoot throughs ( even when a shoot through was impossible).

[xd1977]

I'm running a STI Apeiro with a Schuemann AET Tribird barrel. I have done EVERYTHING to try and stop the keyholing issue with Xtreme plated bullets. I have run 165r and 180r RNFP and HP with regular and concave base at all lengths from 1.135 to 1.19. I even tried reducing the crimp to almost none and it still didn't resolve the problem. I still got a keyhole with every 1 in 8 to 1 in 10. It cost me 2 mikes at a USPSA major match recently because of the non-radius holes.

Then, I called Schuemann. They explained the gain rifle twisting in the AET Barrel and how the gain twisting was actually almost ripping the copper plating off the bullet. After recovering some of my fired plated bullets, I could see exactly what they were talking about. The solution was to buy a Schuemann Bull BarrelI with the regular rifling which was not an option for me. I have since switched to FMJHP Precision Delta Bullets and haven't looked back at plated bullets with the AET barrel. Ever wonder why velocities are a little slower from an AET barrels? From Schuemann's website:

http://www.schuemann.com/Portals/0/Documentation/Webfile_AET_BARRELS.pdf